{
"name": "Basic JavaScript",
"time": "10 hours",
"order": 6,
"helpRoom": "HelpJavaScript",
"challenges": [
{
"id": "bd7123c9c441eddfaeb4bdef",
"title": "Comment your JavaScript Code",
"description": [
"Comments are lines of code that JavaScript will intentionally ignore. Comments are a great way to leave notes to yourself and to other people who will later need to figure out what that code does.",
"There are two ways to write comments in JavaScript:",
"Using // will tell JavaScript to ignore the remainder of the text on the current line:",
"
// This is an in-line comment.
",
"You can make a multi-line comment beginning with /* and ending with */:",
"
/* This is a multi-line comment */
",
"Best Practice As you write code, you should regularly add comments to clarify the function of parts of your code. Good commenting can help communicate the intent of your code—both for others and for your future self.",
"
Instructions
",
"Try creating one of each type of comment."
],
"challengeSeed": [
""
],
"solutions": [
"// Fake Comment\n/* Another Comment */"
],
"tests": [
"assert(code.match(/(\\/\\/)...../g), 'message: Create a // style comment that contains at least five letters.');",
"assert(code.match(/(\\/\\*)[\\w\\W]{5,}(?=\\*\\/)/gm), 'message: Create a /* */ style comment that contains at least five letters.');",
"assert(code.match(/(\\*\\/)/g), 'message: Make sure that you close the comment with a */.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Agrega comentarios a tu código JavaScript",
"descriptionEs": [
"Los comentarios son líneas de código que el computador ignorará intencionalmente. Los comentarios son una gran forma de dejarte notas a ti mismo y a otras personas que luego tendrán que averiguar lo que hace que el código. ",
"Vamos a echar un vistazo a las dos maneras en las que puedes agregar tus comentarios en JavaScript.",
"El comentario de doble barra comentará el resto del texto en la línea donde se ubica:",
"// Este es un comentario.",
"El comentario de barra-estrella-estrella-barra, comentará todo lo que haya entre los caracteres /* y */:",
"/* Este es también un comentario */",
"Trata de crear uno de cada uno."
]
},
{
"id": "bd7123c9c443eddfaeb5bdef",
"title": "Declare JavaScript Variables",
"description": [
"In computer science, data is anything that is meaningful to the computer. JavaScript provides seven different data types which are undefined, null, Boolean, string, symbol, number, and object.",
"For example, computers distinguish between numbers, such as the number 12, and strings, such as \"12\", \"dog\", or \"123 cats\", which are collections of characters. Computers can perform mathematical operations on a number, but not on a string.",
"Variables allow computers to store data in a dynamic fashion, rather than updating a formula every time the data changes. Any of the seven different data types may be stored in a variable.",
"Variables are similar to the x and y variables you use in mathematics, which means they're a simple name to represent the data we want to refer to. Computer variables differ from mathematical variables in that they can store different values at different times.",
"We tell JavaScript to create or declare a variable by putting the keyword var in front of it, like so:",
"
var ourName;
",
"creates a variable called ourName. In JavaScript we end statements with semicolons.",
"Variable names can be made up of numbers, letters, and $ or _, but may not contain spaces or start with a number.",
"
Instructions
",
"Use the var keyword to create a variable called myName.",
"Hint Look at the ourName example if you get stuck."
],
"challengeSeed": [
"// Example",
"var ourName;",
"",
"// Define myName below this line",
""
],
"tail": [
"if(typeof myName !== \"undefined\"){(function(v){return v;})(myName);}"
],
"solutions": [
"var myName;"
],
"tests": [
"assert(/var\\s+myName\\s*;/.test(code), 'message: You should declare myName with the var keyword, ending with a semicolon');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Declara variables en JavaScript",
"descriptionEs": [
"Cuando almacenamos datos en una estructura de datos, la llamamos una variable. Estas variables no son diferentes de las variables x e y que utilizas en matemáticas. ",
"Vamos a crear nuestra primera variable y a llamarla \"myName\".",
"Te darás cuenta que en myName, no usamos un espacio, y que la \" N\"se escribe con mayúscula. Las variables en JavaScript se escriben con capitalización camello (camel case). Un ejemplo de capitalización camello: capitalizacionCamello.",
"Ahora, utiliza la palabra clave var para crear una variable llamada myName. Establecele como valor tu nombre, entre comillas dobles. ",
"Mira el ejemplo con ourName si te quedas atascado."
]
},
{
"id": "56533eb9ac21ba0edf2244a8",
"title": "Storing Values with the Equal Operator",
"description": [
"In JavaScript, you can store a value in a variable with the assignment or equal (=) operator.",
"myVariable = 5;",
"Assigns the Number value 5 to myVariable.",
"Assignment always goes from right to left. Everything to the right of the = operator is resolved before the value is assigned to the variable to the left of the operator.",
"
myVar = 5; myNum = myVar;
",
"Assigns 5 to myVar and then resolves myVar to 5 again and assigns it to myNum.",
"
Instructions
",
"Assign the value 7 to variable a.",
"Assign the contents of a to variable b."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var a;",
"var b = 2;",
"",
"// Only change code below this line",
""
],
"tail": [
"(function(a,b){return \"a = \" + a + \", b = \" + b;})(a,b);"
],
"solutions": [
"var a;\nvar b = 2;\na = 7;\nb = a;"
],
"tests": [
"assert(/var a;/.test(code) && /var b = 2;/.test(code), 'message: Do not change code above the line');",
"assert(typeof a === 'number' && a === 7, 'message: a should have a value of 7');",
"assert(typeof b === 'number' && b === 7, 'message: b should have a value of 7');",
"assert(/b\\s*=\\s*a\\s*;/g.test(code), 'message: a should be assigned to b with =');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244a9",
"title": "Initializing Variables with the Equal Operator",
"description": [
"It is common to initialize a variable to an initial value in the same line as it is declared.",
"var myVar = 0;",
"Creates a new variable called myVar and assigns it an initial value of 0.",
"
Instructions
",
"Define a variable a with var and initialize it to a value of 9."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Example",
"var ourVar = 19;",
"",
"// Only change code below this line",
""
],
"tail": [
"if(typeof a !== 'undefined') {(function(a){return \"a = \" + a;})(a);} else { (function() {return 'a is undefined';})(); }"
],
"solutions": [
"var a = 9;"
],
"tests": [
"assert(/var\\s+a\\s*=\\s*9\\s*/.test(code), 'message: Initialize a to a value of 9');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244aa",
"title": "Understanding Uninitialized Variables",
"description": [
"When JavaScript variables are declared, they have an initial value of undefined. If you do a mathematical operation on an undefined variable your result will be NaN which means \"Not a Number\". If you concatenate a string with an undefined variable, you will get a literal string of \"undefined\".",
"
Instructions
",
"Initialize the three variables a, b, and c with 5, 10, and \"I am a\" respectively so that they will not be undefined."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Initialize these three variables",
"var a;",
"var b;",
"var c;",
"",
"// Do not change code below this line",
"",
"a = a + 1;",
"b = b + 5;",
"c = c + \" String!\";",
""
],
"tail": [
"(function(a,b,c){ return \"a = \" + a + \", b = \" + b + \", c = '\" + c + \"'\"; })(a,b,c);"
],
"solutions": [
"var a = 5;\nvar b = 10;\nvar c = \"I am a\";\na = a + 1;\nb = b + 5;\nc = c + \" String!\";"
],
"tests": [
"assert(typeof a === 'number' && a === 6, 'message: a should be defined and have a value of 6');",
"assert(typeof b === 'number' && b === 15, 'message: b should be defined and have a value of 15');",
"assert(!/undefined/.test(c) && c === \"I am a String!\", 'message: c should not contain undefined and should have a value of \"I am a String!\"');",
"assert(/a = a \\+ 1;/.test(code) && /b = b \\+ 5;/.test(code) && /c = c \\+ \" String!\";/.test(code), 'message: Do not change code below the line');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244ab",
"title": "Understanding Case Sensitivity in Variables",
"description": [
"In JavaScript all variables and function names are case sensitive. This means that capitalization matters.",
"MYVAR is not the same as MyVar nor myvar. It is possible to have multiple distinct variables with the same name but different casing. It is strongly recommended that for the sake of clarity, you do not use this language feature.",
"
Best Practice
",
"Write variable names in Javascript in camelCase. In camelCase, multi-word variable names have the first word in lowercase and the first letter of each subsequent word is capitalized.",
"Examples:",
"
var someVariable; var anotherVariableName; var thisVariableNameIsTooLong;
",
"
Instructions
",
"Fix the variable declarations and assignments so their names use camelCase."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Declarations",
"var StUdLyCapVaR;",
"var properCamelCase;",
"var TitleCaseOver;",
"",
"// Assignments",
"STUDLYCAPVAR = 10;",
"PRoperCAmelCAse = \"A String\";",
"tITLEcASEoVER = 9000;"
],
"solutions": [
"var studlyCapVar;\nvar properCamelCase;\nvar titleCaseOver;\n\nstudlyCapVar = 10;\nproperCamelCase = \"A String\";\ntitleCaseOver = 9000;"
],
"tests": [
"assert(typeof studlyCapVar !== 'undefined' && studlyCapVar === 10, 'message: studlyCapVar is defined and has a value of 10');",
"assert(typeof properCamelCase !== 'undefined' && properCamelCase === \"A String\", 'message: properCamelCase is defined and has a value of \"A String\"');",
"assert(typeof titleCaseOver !== 'undefined' && titleCaseOver === 9000, 'message: titleCaseOver is defined and has a value of 9000');",
"assert(code.match(/studlyCapVar/g).length === 2, 'message: studlyCapVar should use camelCase in both declaration and assignment sections.');",
"assert(code.match(/properCamelCase/g).length === 2, 'message: properCamelCase should use camelCase in both declaration and assignment sections.');",
"assert(code.match(/titleCaseOver/g).length === 2, 'message: titleCaseOver should use camelCase in both declaration and assignment sections.');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "cf1111c1c11feddfaeb3bdef",
"title": "Add Two Numbers with JavaScript",
"description": [
"Number is a data type in JavaScript which represents numeric data.",
"Now let's try to add two numbers using JavaScript.",
"JavaScript uses the + symbol as addition operation when placed between two numbers.",
"",
"Example",
"
myVar = 5 + 10; // assigned 15
",
"",
"
Instructions
",
"Change the 0 so that sum will equal 20."
],
"challengeSeed": [
"var sum = 10 + 0;",
""
],
"tail": [
"(function(z){return 'sum='+z;})(sum);"
],
"solutions": [
"var sum = 10 + 10;"
],
"tests": [
"assert(sum === 20, 'message: sum should equal 20');",
"assert(/\\+/.test(code), 'message: Use the + operator');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Suma dos números con JavaScript",
"descriptionEs": [
"Intentemos sumar dos números con JavaScript.",
"JavaScript utiliza el símbolo + para la adición.",
"Cambie el 0 para que la suma seá igual a 20."
]
},
{
"id": "cf1111c1c11feddfaeb4bdef",
"title": "Subtract One Number from Another with JavaScript",
"description": [
"We can also subtract one number from another.",
"JavaScript uses the - symbol for subtraction.",
"",
"Example",
"
myVar = 12 - 6; // assigned 6
",
"",
"
Instructions
",
"Change the 0 so the difference is 12."
],
"challengeSeed": [
"var difference = 45 - 0;",
"",
""
],
"tail": [
"(function(z){return 'difference='+z;})(difference);"
],
"solutions": [
"var difference = 45 - 33;"
],
"tests": [
"assert(difference === 12, 'message: Make the variable difference equal 12.');",
"assert((code).match(/difference/g).length === 1,'message: Only change the first line');",
"assert(/\\d+\\s*-\\s*\\d+/.test(code),'message: Use the - operator');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Resta un número de otro con JavaScript",
"descriptionEs": [
"También podemos restar un número de otro.",
"JavaScript utiliza el símbolo - de sustracción",
"Cambia el 0 para que la diferencia sea 12."
]
},
{
"id": "cf1231c1c11feddfaeb5bdef",
"title": "Multiply Two Numbers with JavaScript",
"description": [
"We can also multiply one number by another.",
"JavaScript uses the * symbol for multiplication of two numbers.",
"",
"Example",
"
myVar = 13 * 13; // assigned 169
",
"",
"
Instructions
",
"Change the 0 so that product will equal 80."
],
"challengeSeed": [
"var product = 8 * 0;",
"",
""
],
"tail": [
"(function(z){return 'product = '+z;})(product);"
],
"solutions": [
"var product = 8 * 10;"
],
"tests": [
"assert(product === 80,'message: Make the variable product equal 80');",
"assert(/\\*/.test(code), 'message: Use the * operator');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Multiplica dos números con JavaScript",
"descriptionEs": [
"También podemos multiplicar un número por otro.",
"JavaScript utiliza el símbolo * de la multiplicación.",
"Cambie el 0 para que el producto sea igual a 80."
]
},
{
"id": "cf1111c1c11feddfaeb6bdef",
"title": "Divide One Number by Another with JavaScript",
"description": [
"We can also divide one number by another.",
"JavaScript uses the / symbol for division.",
"",
"Example",
"
myVar = 16 / 2; // assigned 8
",
"",
"
Instructions
",
"Change the 0 so that the quotient is equal to 2."
],
"challengeSeed": [
"var quotient = 66 / 0;",
"",
""
],
"tail": [
"(function(z){return 'quotient = '+z;})(quotient);"
],
"solutions": [
"var quotient = 66 / 33;"
],
"tests": [
"assert(quotient === 2, 'message: Make the variable quotient equal to 2.');",
"assert(/\\d+\\s*\\/\\s*\\d+/.test(code), 'message: Use the / operator');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Divide un número por otro con JavaScript",
"descriptionEs": [
"También podemos dividir un número por otro.",
"JavaScript utiliza el símbolo / para dividir.",
"Cambia el 0 para que el cociente sea igual a 2."
]
},
{
"id": "56533eb9ac21ba0edf2244ac",
"title": "Increment a Number with Javascript",
"description": [
"You can easily increment or add one to a variable with the ++ operator.",
"i++;",
"is the equivalent of",
"i = i + 1;",
"Note The entire line becomes i++;, eliminating the need for the equal sign.",
"
Instructions
",
"Change the code to use the ++ operator on myVar."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var myVar = 87;",
"",
"// Only change code below this line",
"myVar = myVar + 1;",
""
],
"tail": [
"(function(z){return 'myVar = ' + z;})(myVar);"
],
"solutions": [
"var myVar = 87;\nmyVar++;"
],
"tests": [
"assert(myVar === 88, 'message: myVar should equal 88');",
"assert(/myVar\\s*[+]{2}/.test(code), 'message: Use the ++ operator');",
"assert(/var myVar = 87;/.test(code), 'message: Do not change code above the line');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244ad",
"title": "Decrement a Number with Javascript",
"description": [
"You can easily decrement or decrease a variable by one with the -- operator.",
"i--;",
"is the equivalent of",
"i = i - 1;",
"Note The entire line becomes i--;, eliminating the need for the equal sign.",
"
Instructions
",
"Change the code to use the -- operator on myVar."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var myVar = 11;",
"",
"// Only change code below this line",
"myVar = myVar - 1;",
""
],
"tail": [
"(function(z){return 'myVar = ' + z;})(myVar);"
],
"solutions": [
"var myVar = 11;\nmyVar--;"
],
"tests": [
"assert(myVar === 10, 'message: myVar should equal 10');",
"assert(/myVar\\s*[-]{2}/.test(code), 'message: Use the -- operator on myVar');",
"assert(/var myVar = 11;/.test(code), 'message: Do not change code above the line');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "cf1391c1c11feddfaeb4bdef",
"title": "Create Decimal Numbers with JavaScript",
"description": [
"We can store decimal numbers in variables too. Decimal numbers are sometimes referred to as floating point numbers or floats.",
"Note Not all real numbers can accurately be represented in floating point. This can lead to rounding errors. Details Here.",
"
Instructions
",
"Create a variable myDecimal and give it a decimal value with a fractional part (e.g. 5.7)."
],
"challengeSeed": [
"var ourDecimal = 5.7;",
"",
"// Only change code below this line",
"",
""
],
"tail": [
"(function(){if(typeof myDecimal !== \"undefined\"){return myDecimal;}})();"
],
"solutions": [
"var myDecimal = 9.9;"
],
"tests": [
"assert(typeof myDecimal === \"number\", 'message: myDecimal should be a number.');",
"assert(myDecimal % 1 != 0, 'message: myDecimal should have a decimal point'); "
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Crea números decimales con JavaScript",
"descriptionEs": [
"Las variables tipo número en JavaScript también pueden tener decimales.",
"Vamos a crear una variable myDecimal y a darle un valor decimal."
]
},
{
"id": "bd7993c9c69feddfaeb7bdef",
"title": "Multiply Two Decimals with JavaScript",
"description": [
"In JavaScript, you can also perform calculations with decimal numbers, just like whole numbers.",
"Let's multiply two decimals together to get their product.",
"
Instructions
",
"Change the 0.0 so that product will equal 5.0."
],
"challengeSeed": [
"var product = 2.0 * 0.0;",
"",
""
],
"tail": [
"(function(y){return 'product = '+y;})(product);"
],
"solutions": [
"var product = 2.0 * 2.5;"
],
"tests": [
"assert(product === 5.0, 'message: The variable product should equal 5.0.');",
"assert(/\\*/.test(code), 'message: You should use the * operator');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Multiplica dos decimales con JavaScript",
"descriptionEs": [
"En JavaScript, también puedes realizar cálculos con números decimales, al igual que con números enteros.",
"Vamos a multiplicar dos números decimales para obtener su producto.",
"Cambia el 0.0 para que el producto sea igual a 5.0."
]
},
{
"id": "bd7993c9ca9feddfaeb7bdef",
"title": "Divide one Decimal by Another with JavaScript",
"description": [
"Now let's divide one decimal by another.",
"
Instructions
",
"Change the 0.0 so that quotient will equal to 2.2."
],
"challengeSeed": [
"var quotient = 0.0 / 2.0;",
"",
""
],
"tail": [
"(function(y){return 'quotient = '+y;})(quotient);"
],
"solutions": [
"var quotient = 4.4 / 2.0;"
],
"tests": [
"assert(quotient === 2.2, 'message: The variable quotient should equal 2.2.');",
"assert(/\\//.test(code), 'message: You should use the / operator');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Divide un número decimal por otro con JavaScript",
"descriptionEs": [
"Ahora vamos a dividir un decimal por otro.",
"Cambia el 0.0 para que tu cociente sea igual a 2.2."
]
},
{
"id": "56533eb9ac21ba0edf2244ae",
"title": "Finding a Remainder in Javascript",
"description": [
"The remainder operator % gives the remainder of the division of two numbers.",
"Example",
"
",
"Usage In mathematics, a number can be checked even or odd by checking the remainder of the division of the number by 2.",
"
17 % 2 = 1 (17 is Odd) 48 % 2 = 0 (48 is Even)
",
"Note The remainder operator is sometimes incorrectly referred to as the \"modulus\" operator. It is very similar to modulus, but does not work properly with negative numbers.",
"
Instructions
",
"Set remainder equal to the remainder of 11 divided by 3 using the remainder (%) operator."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Only change code below this line",
"",
"var remainder;",
""
],
"tail": [
"(function(y){return 'remainder = '+y;})(remainder);"
],
"solutions": [
"var remainder = 11 % 3;"
],
"tests": [
"assert(remainder === 2, 'message: The value of remainder should be 2');",
"assert(/\\d+\\s*%\\s*\\d+/.test(code), 'message: You should use the % operator');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244af",
"title": "Assignment with Plus Equals",
"description": [
"In programming, it is common to use assignments to modify the contents of a variable. Remember that everything to the right of the equals sign is evaluated first, so we can say:",
"myVar = myVar + 5;",
"to add 5 to myVar. Since this is such a common pattern, there are operators which do both a mathematical operation and assignment in one step.",
"One such operator is the += operator.",
"myVar += 5; will add 5 to myVar.",
"
Instructions
",
"Convert the assignments for a, b, and c to use the += operator."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var a = 3;",
"var b = 17;",
"var c = 12;",
"",
"// Only modify code below this line",
"",
"a = a + 12;",
"b = 9 + b;",
"c = c + 7;",
""
],
"tail": [
"(function(a,b,c){ return \"a = \" + a + \", b = \" + b + \", c = \" + c; })(a,b,c);"
],
"solutions": [
"var a = 3;\nvar b = 17;\nvar c = 12;\n\na += 12;\nb += 9;\nc += 7;"
],
"tests": [
"assert(a === 15, 'message: a should equal 15');",
"assert(b === 26, 'message: b should equal 26');",
"assert(c === 19, 'message: c should equal 19');",
"assert(code.match(/\\+=/g).length === 3, 'message: You should use the += operator for each variable');",
"assert(/var a = 3;/.test(code) && /var b = 17;/.test(code) && /var c = 12;/.test(code), 'message: Do not modify the code above the line');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b0",
"title": "Assignment with Minus Equals",
"description": [
"Like the += operator, -= subtracts a number from a variable.",
"myVar = myVar - 5;",
"will subtract 5 from myVar. This can be rewritten as: ",
"myVar -= 5;",
"
Instructions
",
"Convert the assignments for a, b, and c to use the -= operator."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var a = 11;",
"var b = 9;",
"var c = 3;",
"",
"// Only modify code below this line",
"",
"a = a - 6;",
"b = b - 15;",
"c = c - 1;",
"",
""
],
"tail": [
"(function(a,b,c){ return \"a = \" + a + \", b = \" + b + \", c = \" + c; })(a,b,c);"
],
"solutions": [
"var a = 11;\nvar b = 9;\nvar c = 3;\n\na -= 6;\nb -= 15;\nc -= 1;\n\n"
],
"tests": [
"assert(a === 5, 'message: a should equal 5');",
"assert(b === -6, 'message: b should equal -6');",
"assert(c === 2, 'message: c should equal 2');",
"assert(code.match(/-=/g).length === 3, 'message: You should use the -= operator for each variable');",
"assert(/var a = 11;/.test(code) && /var b = 9;/.test(code) && /var c = 3;/.test(code), 'message: Do not modify the code above the line');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b1",
"title": "Assignment with Times Equals",
"description": [
"The *= operator multiplies a variable by a number.",
"myVar = myVar * 5;",
"will multiply myVar by 5. This can be rewritten as: ",
"myVar *= 5;",
"
Instructions
",
"Convert the assignments for a, b, and c to use the *= operator."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var a = 5;",
"var b = 12;",
"var c = 4.6;",
"",
"// Only modify code below this line",
"",
"a = a * 5;",
"b = 3 * b;",
"c = c * 10;",
"",
""
],
"tail": [
"(function(a,b,c){ return \"a = \" + a + \", b = \" + b + \", c = \" + c; })(a,b,c);"
],
"solutions": [
"var a = 5;\nvar b = 12;\nvar c = 4.6;\n\na *= 5;\nb *= 3;\nc *= 10;"
],
"tests": [
"assert(a === 25, 'message: a should equal 25');",
"assert(b === 36, 'message: b should equal 36');",
"assert(c === 46, 'message: c should equal 46');",
"assert(code.match(/\\*=/g).length === 3, 'message: You should use the *= operator for each variable');",
"assert(/var a = 5;/.test(code) && /var b = 12;/.test(code) && /var c = 4\\.6;/.test(code), 'message: Do not modify the code above the line');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b2",
"title": "Assignment with Divided by Equals",
"description": [
"The /= operator divides a variable by another number.",
"myVar = myVar / 5;",
"Will divide myVar by 5. This can be rewritten as: ",
"myVar /= 5;",
"
Instructions
",
"Convert the assignments for a, b, and c to use the /= operator."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var a = 48;",
"var b = 108;",
"var c = 33;",
"",
"// Only modify code below this line",
"",
"a = a / 12;",
"b = b / 4;",
"c = c / 11;",
""
],
"tail": [
"(function(a,b,c){ return \"a = \" + a + \", b = \" + b + \", c = \" + c; })(a,b,c);"
],
"solutions": [
"var a = 48;\nvar b = 108;\nvar c = 33;\n\na /= 12;\nb /= 4;\nc /= 11;"
],
"tests": [
"assert(a === 4, 'message: a should equal 4');",
"assert(b === 27, 'message: b should equal 27');",
"assert(c === 3, 'message: c should equal 3');",
"assert(code.match(/\\/=/g).length === 3, 'message: You should use the /= operator for each variable');",
"assert(/var a = 48;/.test(code) && /var b = 108;/.test(code) && /var c = 33;/.test(code), 'message: Do not modify the code above the line');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b3",
"title": "Convert Celsius to Fahrenheit",
"description": [
"To test your learning you will create a solution \"from scratch\". Place your code between the indicated lines and it will be tested against multiple test cases.",
"The algorithm to convert from Celsius to Fahrenheit is the temperature in Celsius times 9/5, plus 32.",
"You are given a variable celsius representing a temperature in Celsius. Create a variable fahrenheit and apply the algorithm to assign it the corresponding temperature in Fahrenheit."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function convert(celsius) {",
" // Only change code below this line",
" ",
"",
" // Only change code above this line",
" if ( typeof fahrenheit !== 'undefined' ) {",
" return fahrenheit;",
" } else {",
" return 'fahrenheit not defined';",
" }",
"}",
"",
"// Change the inputs below to test your code",
"convert(30);"
],
"solutions": [
"function convert(celsius) {\n var fahrenheit = celsius * 9/5 + 32;\n if ( typeof fahrenheit !== 'undefined' ) {\n return fahrenheit;\n } else {\n return 'fahrenheit not defined';\n }\n}"
],
"tests": [
"assert(typeof convert(0) === 'number', 'message: convert(0) should return a number');",
"assert(convert(-30) === -22, 'message: convert(-30) should return a value of -22');",
"assert(convert(-10) === 14, 'message: convert(-10) should return a value of 14');",
"assert(convert(0) === 32, 'message: convert(0) should return a value of 32');",
"assert(convert(20) === 68, 'message: convert(20) should return a value of 68');",
"assert(convert(30) === 86, 'message: convert(30) should return a value of 86');"
],
"type": "checkpoint",
"challengeType": 1
},
{
"id": "bd7123c9c444eddfaeb5bdef",
"title": "Declare String Variables",
"description": [
"Previously we have used the code",
"var myName = \"your name\";",
"\"your name\" is called a string literal. It is a string because it is a series of zero or more characters enclosed in single or double quotes.",
"
Instructions
",
"Create two new string variables: myFirstName and myLastName and assign them the values of your first and last name, respectively."
],
"challengeSeed": [
"// Example",
"var firstName = \"Alan\";",
"var lastName = \"Turing\";",
"",
"// Only change code below this line",
"",
"",
""
],
"tail": [
"if(typeof myFirstName !== \"undefined\" && typeof myLastName !== \"undefined\"){(function(){return myFirstName + ', ' + myLastName;})();}"
],
"solutions": [
"var myFirstName = \"Alan\";\nvar myLastName = \"Turing\";"
],
"tests": [
"assert((function(){if(typeof myFirstName !== \"undefined\" && typeof myFirstName === \"string\" && myFirstName.length > 0){return true;}else{return false;}})(), 'message: myFirstName should be a string with at least one character in it.');",
"assert((function(){if(typeof myLastName !== \"undefined\" && typeof myLastName === \"string\" && myLastName.length > 0){return true;}else{return false;}})(), 'message: myLastName should be a string with at least one character in it.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Declara variables tipo cadena",
"descriptionEs": [
"En el reto anterior, se utilizó el código myName var = \"su nombre\". Esto es lo que llamamos una variable tipo cadena. No es nada más que una \"cadena\" de caracteres. Las cadenas en JavaScript siempre se encierran entre comillas. ",
"Ahora vamos a crear dos nuevas variables tipo cadena: myFirstName y myLastName y asignarles los valores de tu nombre y tu apellido, respectivamente."
]
},
{
"id": "56533eb9ac21ba0edf2244b5",
"title": "Escaping Literal Quotes in Strings",
"description": [
"When you are defining a string you must start and end with a single or double quote. What happens when you need a literal quote: \" or ' inside of your string?",
"In JavaScript, you can escape a quote from considering it as an end of string quote by placing a backslash (\\) in front of the quote.",
"var sampleStr = \"Alan said, \\\"Peter is learning JavaScript\\\".\";",
"This signals to JavaScript that the following quote is not the end of the string, but should instead appear inside the string. So if you were to print this to the console, you would get:",
"Alan said, \"Peter is learning JavaScript\".",
"
Instruction
",
"Use backslashes to assign a string to the myStr variable so that if you were to print it to the console, you would see:",
"I am a \"double quoted\" string inside \"double quotes\""
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var myStr; // Change this line",
"",
""
],
"tail": [
"(function(){",
" if(typeof myStr === 'string') {",
" return \"myStr = \" + myStr;",
" } else {",
" return \"myStr is undefined\";",
" }",
"})();"
],
"solutions": [
"var myStr = \"I am a \\\"double quoted\\\" string inside \\\"double quotes\\\"\";"
],
"tests": [
"assert(code.match(/\\\\\"/g).length === 4 && code.match(/[^\\\\]\"/g).length === 2, 'message: You should use two double quotes (") and four escaped double quotes (\") ');",
"assert(myStr === \"I am a \\\"double quoted\\\" string inside \\\"double quotes\\\"\", 'message: Variable myStr should equal to (\"I am a \"double quoted\" string inside \"double quotes\"\").');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b4",
"title": "Quoting Strings with Single Quotes",
"description": [
"String values in JavaScript may be written with single or double quotes, so long as you start and end with the same type of quote. Unlike some languages, single and double quotes are functionally identical in Javascript.",
"\"This string has \\\"double quotes\\\" in it\"",
"The value in using one or the other has to do with the need to escape quotes of the same type. If you have a string with many double quotes, this can be difficult to read and write. Instead, use single quotes:",
"'This string has \"double quotes\" in it. And \"probably\" lots of them.'",
"
Instructions
",
"Change the provided string from double to single quotes and remove the escaping."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var myStr = \"Link\";",
"",
""
],
"tail": [
"(function() { return \"myStr = \" + myStr; })();"
],
"solutions": [
"var myStr = 'Link';"
],
"tests": [
"assert(!/\\\\/g.test(code), 'message: Remove all the backslashes (\\)');",
"assert(code.match(/\"/g).length === 4 && code.match(/'/g).length === 2, 'message: You should have two single quotes ' and four double quotes "');",
"assert(myStr === 'Link', 'message: Only remove the backslashes \\ used to escape quotes.');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b6",
"title": "Escape Sequences in Strings",
"description": [
"Quotes are not the only characters that can be escaped inside a string. Here is a table of common escape sequences:",
"
Code
Output
\\'
single quote
\\\"
double quote
\\\\
backslash
\\n
new line
\\r
carriage return
\\t
tab
\\b
backspace
\\f
form feed
",
"Note that the backslash itself must be escaped in order to display as a backslash.",
"
Instructions
",
"Encode the following sequence, separated by spaces: backslash tab tab carriage-return new-line and assign it to myStr"
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var myStr; // Change this line",
"",
""
],
"tail": [
"(function(){",
"if (myStr !== undefined){",
"return 'myStr = '+ JSON.stringify(myStr);}",
"else{return null;}})();"
],
"solutions": [
"var myStr = \"\\\\ \\t \\t \\r \\n\";"
],
"tests": [
"assert(myStr === \"\\\\ \\t \\t \\r \\n\", 'message: myStr should have the escape sequences for backslash tab tab carriage-return new-line separated by spaces');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b7",
"title": "Concatenating Strings with Plus Operator",
"description": [
"In JavaScript, when the + operator is used with a String value, it is called the concatenation operator. You can build a new string out of other strings by concatenating them together.",
"Example",
"
'My name is Alan,' + ' I concatenate.'
",
"Note Watch out for spaces. Concatenation does not add spaces between concatenated strings, so you'll need to add them yourself.",
"
Instructions
",
"Build myStr from the strings \"This is the start. \" and \"This is the end.\" using the + operator."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Example",
"var ourStr = \"I come first. \" + \"I come second.\";",
"",
"// Only change code below this line",
"",
"var myStr;",
"",
""
],
"tail": [
"(function(){",
" if(typeof myStr === 'string') {",
" return 'myStr = \"' + myStr + '\"';",
" } else {",
" return 'myStr is not a string';",
" }",
"})();"
],
"solutions": [
"var ourStr = \"I come first. \" + \"I come second.\";\nvar myStr = \"This is the start. \" + \"This is the end.\";"
],
"tests": [
"assert(myStr === \"This is the start. This is the end.\", 'message: myStr should have a value of This is the start. This is the end.');",
"assert(code.match(/([\"']).*([\"'])\\s*\\+\\s*([\"']).*([\"'])/g).length > 1, 'message: Use the + operator to build myStr');",
"assert(/var\\s+myStr/.test(code), 'message: myStr should be created using the var keyword.');",
"assert(/myStr\\s*=/.test(code), 'message: Make sure to assign the result to the myStr variable.');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b8",
"title": "Concatenating Strings with the Plus Equals Operator",
"description": [
"We can also use the += operator to concatenate a string onto the end of an existing string variable. This can be very helpful to break a long string over several lines.",
"Note Watch out for spaces. Concatenation does not add spaces between concatenated strings, so you'll need to add them yourself.",
"
Instructions
",
"Build myStr over several lines by concatenating these two strings: \"This is the first sentence. \" and \"This is the second sentence.\" using the += operator."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Example",
"var ourStr = \"I come first. \";",
"ourStr += \"I come second.\";",
"",
"// Only change code below this line",
"",
"var myStr;",
"",
""
],
"tail": [
"(function(){",
" if(typeof myStr === 'string') {",
" return 'myStr = \"' + myStr + '\"';",
" } else {",
" return 'myStr is not a string';",
" }",
"})();"
],
"solutions": [
"var ourStr = \"I come first. \";\nourStr += \"I come second.\";\n\nvar myStr = \"This is the first sentence. \";\nmyStr += \"This is the second sentence.\";"
],
"tests": [
"assert(myStr === \"This is the first sentence. This is the second sentence.\", 'message: myStr should have a value of This is the first sentence. This is the second sentence.');",
"assert(code.match(/\\w\\s*\\+=\\s*[\"']/g).length > 1 && code.match(/\\w\\s*\\=\\s*[\"']/g).length > 1, 'message: Use the += operator to build myStr');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244b9",
"title": "Constructing Strings with Variables",
"description": [
"Sometimes you will need to build a string, Mad Libs style. By using the concatenation operator (+), you can insert one or more variables into a string you're building.",
"
Instructions
",
"Set myName to a string equal to your name and build myStr with myName between the strings \"My name is \" and \" and I am swell!\""
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Example",
"var ourName = \"Free Code Camp\";",
"var ourStr = \"Hello, our name is \" + ourName + \", how are you?\";",
"",
"// Only change code below this line",
"var myName;",
"var myStr;",
"",
""
],
"tail": [
"(function(){",
" var output = [];",
" if(typeof myName === 'string') {",
" output.push('myName = \"' + myName + '\"');",
" } else {",
" output.push('myName is not a string');",
" }",
" if(typeof myStr === 'string') {",
" output.push('myStr = \"' + myStr + '\"');",
" } else {",
" output.push('myStr is not a string');",
" }",
" return output.join('\\n');",
"})();"
],
"solutions": [
"var myName = \"Bob\";\nvar myStr = \"My name is \" + myName + \" and I am swell!\";"
],
"tests": [
"assert(typeof myName !== 'undefined' && myName.length > 2, 'message: myName should be set to a string at least 3 characters long');",
"assert(code.match(/[\"']\\s*\\+\\s*myName\\s*\\+\\s*[\"']/g).length > 0, 'message: Use two + operators to build myStr with myName inside it');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244ed",
"title": "Appending Variables to Strings",
"description": [
"Just as we can build a string over multiple lines out of string literals, we can also append variables to a string using the plus equals (+=) operator.",
"
Instructions
",
"Set someAdjective and append it to myStr using the += operator."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Example",
"var anAdjective = \"awesome!\";",
"var ourStr = \"Free Code Camp is \";",
"ourStr += anAdjective;",
"",
"// Only change code below this line",
"",
"var someAdjective;",
"var myStr = \"Learning to code is \";",
""
],
"tail": [
"(function(){",
" var output = [];",
" if(typeof someAdjective === 'string') {",
" output.push('someAdjective = \"' + someAdjective + '\"');",
" } else {",
" output.push('someAdjective is not a string');",
" }",
" if(typeof myStr === 'string') {",
" output.push('myStr = \"' + myStr + '\"');",
" } else {",
" output.push('myStr is not a string');",
" }",
" return output.join('\\n');",
"})();"
],
"solutions": [
"var anAdjective = \"awesome!\";\nvar ourStr = \"Free Code Camp is \";\nourStr += anAdjective;\n\nvar someAdjective = \"neat\";\nvar myStr = \"Learning to code is \";\nmyStr += someAdjective;"
],
"tests": [
"assert(typeof someAdjective !== 'undefined' && someAdjective.length > 2, 'message: someAdjective should be set to a string at least 3 characters long');",
"assert(code.match(/\\w\\s*\\+=\\s*someAdjective\\s*;/).length > 0, 'message: Append someAdjective to myStr using the += operator');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "bd7123c9c448eddfaeb5bdef",
"title": "Find the Length of a String",
"description": [
"You can find the length of a String value by writing .length after the string variable or string literal.",
"\"Alan Peter\".length; // 10",
"For example, if we created a variable var firstName = \"Charles\", we could find out how long the string \"Charles\" is by using the firstName.length property.",
"
Instructions
",
"Use the .length property to count the number of characters in the lastName variable and assign it to lastNameLength."
],
"challengeSeed": [
"// Example",
"var firstNameLength = 0;",
"var firstName = \"Ada\";",
"",
"firstNameLength = firstName.length;",
"",
"// Setup",
"var lastNameLength = 0;",
"var lastName = \"Lovelace\";",
"",
"// Only change code below this line.",
"",
"lastNameLength = lastName;",
"",
""
],
"tail": [
"if(typeof lastNameLength !== \"undefined\"){(function(){return lastNameLength;})();}"
],
"solutions": [
"var firstNameLength = 0;\nvar firstName = \"Ada\";\nfirstNameLength = firstName.length;\n\nvar lastNameLength = 0;\nvar lastName = \"Lovelace\";\nlastNameLength = lastName.length;"
],
"tests": [
"assert((function(){if(typeof lastNameLength !== \"undefined\" && typeof lastNameLength === \"number\" && lastNameLength === 8){return true;}else{return false;}})(), 'message: lastNameLength should be equal to eight.');",
"assert((function(){if(code.match(/\\.length/gi) && code.match(/\\.length/gi).length >= 2 && code.match(/var lastNameLength \\= 0;/gi) && code.match(/var lastNameLength \\= 0;/gi).length >= 1){return true;}else{return false;}})(), 'message: You should be getting the length of lastName by using .length like this: lastName.length.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Comprueba la propiedad longitud (length) de una variable tipo cadena",
"descriptionEs": [
"Las estructuras de datos tienen propiedades. Por ejemplo, las cadenas tienen una propiedad llamada .length que te dirá cuántos caracteres hay en la cadena.",
"Por ejemplo, si creamos una variable var firstName=\"Charles\", podemos averiguar la longitud de la cadena \"Charles\" usando la propiedad firstName.length. ",
"Usa la propiedad .length para contar el número de caracteres en el variable lastName."
]
},
{
"id": "bd7123c9c549eddfaeb5bdef",
"title": "Use Bracket Notation to Find the First Character in a String",
"description": [
"Bracket notation is a way to get a character at a specific index within a string.",
"Most modern programming languages, like JavaScript, don't start counting at 1 like humans do. They start at 0. This is referred to as Zero-based indexing.",
"For example, the character at index 0 in the word \"Charles\" is \"C\". So if var firstName = \"Charles\", you can get the value of the first letter of the string by using firstName[0].",
"
Instructions
",
"Use bracket notation to find the first character in the lastName variable and assign it to firstLetterOfLastName.",
"Hint Try looking at the firstLetterOfFirstName variable declaration if you get stuck."
],
"challengeSeed": [
"// Example",
"var firstLetterOfFirstName = \"\";",
"var firstName = \"Ada\";",
"",
"firstLetterOfFirstName = firstName[0];",
"",
"// Setup",
"var firstLetterOfLastName = \"\";",
"var lastName = \"Lovelace\";",
"",
"// Only change code below this line",
"firstLetterOfLastName = lastName;",
""
],
"tail": [
"(function(v){return v;})(firstLetterOfLastName);"
],
"solutions": [
"var firstLetterOfLastName = \"\";\nvar lastName = \"Lovelace\";\n\n// Only change code below this line\nfirstLetterOfLastName = lastName[0];"
],
"tests": [
"assert(firstLetterOfLastName === 'L', 'message: The firstLetterOfLastName variable should have the value of L.');",
"assert(code.match(/firstLetterOfLastName\\s*=\\s*lastName\\s*\\[\\s*\\d+\\s*\\]/), 'message: You should use bracket notation.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Usa la notación de corchetes para encontrar el primer acaracter de una cadena",
"descriptionEs": [
"La notación de corchetes es una forma de obtener el caracter en un índice específico de una cadena.",
"Los computadoras no empiezan a contar desde 1 como hacen los humanos. Comienzan en 0 ",
"Por ejemplo, el caracter en el índice 0 en la palabra \"Charles \" es \"C\". Entonces si var firstName = \"Charles\", puedes obtener la primera letra de la cadena usando firstName[0] .",
"Usa la notación de corchetes para encontrar el primer caracter en la variable lastName y asignarlo a firstLetterOfLastName.",
"Si te atascas intenta mirar la declaración de la variable firstLetterOfFirstName."
]
},
{
"id": "56533eb9ac21ba0edf2244ba",
"title": "Understand String Immutability",
"description": [
"In Javascript, String values are immutable, which means that they cannot be altered once created.",
"For example, the following code:",
"
var myStr = \"Bob\"; myStr[0] = \"J\";
",
"cannot change the value of myStr to \"Job\", because the contents of myStr cannot be altered. Note that this does not mean that myStr cannot be changed, just that the individual characters of a string literal cannot be changed. The only way to change myStr would be to assign it with a new string, like this:",
"
var myStr = \"Bob\"; myStr = \"Job\";
",
"
Instructions
",
"Correct the assignment to myStr to achieve the desired effect."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var myStr = \"Jello World\";",
"",
"// Only change code below this line",
"",
"myStr[0] = \"H\"; // Fix Me",
"",
""
],
"tail": [
"(function(v){return \"myStr = \" + v;})(myStr);"
],
"solutions": [
"var myStr = \"Jello World\";\nmyStr = \"Hello World\";"
],
"tests": [
"assert(myStr === \"Hello World\", 'message: myStr should have a value of Hello World');",
"assert(/myStr = \"Jello World\"/.test(code), 'message: Do not change the code above the line');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "bd7123c9c450eddfaeb5bdef",
"title": "Use Bracket Notation to Find the Nth Character in a String",
"description": [
"You can also use bracket notation to get the character at other positions within a string.",
"Remember that computers start counting at 0, so the first character is actually the zeroth character.",
"
Instructions
",
"Let's try to set thirdLetterOfLastName to equal the third letter of the lastName variable using bracket notation.",
"Hint Try looking at the secondLetterOfFirstName variable declaration if you get stuck."
],
"challengeSeed": [
"// Example",
"var firstName = \"Ada\";",
"var secondLetterOfFirstName = firstName[1];",
"",
"// Setup",
"var lastName = \"Lovelace\";",
"",
"// Only change code below this line.",
"var thirdLetterOfLastName = lastName;",
"",
""
],
"tail": [
"(function(v){return v;})(thirdLetterOfLastName);"
],
"solutions": [
"var lastName = \"Lovelace\";\nvar thirdLetterOfLastName = lastName[2];"
],
"tests": [
"assert(thirdLetterOfLastName === 'v', 'message: The thirdLetterOfLastName variable should have the value of v.');",
"assert(code.match(/thirdLetterOfLastName\\s*=\\s*lastName\\s*\\[\\s*\\d+\\s*\\]/), 'message: You should use bracket notation.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Usa la notación de corchetes para encontrar el n-ésimo caracter en una cadena",
"descriptionEs": [
"También puede usar notación de corchetes para obtener el caracter en otras posiciones dentro de una cadena.",
"Recuerda que los computadores empiezan a contar a 0, por lo que el primer caracter es en realidad el caracter cero.",
"Vamos a tratar de asignar a thirdLetterOfLastName la tercera letra de la variable lastName.",
"Si te atascas intenta mirar la declaración de la variable secondLetterOfFirstName."
]
},
{
"id": "bd7123c9c451eddfaeb5bdef",
"title": "Use Bracket Notation to Find the Last Character in a String",
"description": [
"In order to get the last letter of a string, you can subtract one from the string's length.",
"For example, if var firstName = \"Charles\", you can get the value of the last letter of the string by using firstName[firstName.length - 1].",
"
Instructions
",
"Use bracket notation to find the last character in the lastName variable.",
"Hint Try looking at the lastLetterOfFirstName variable declaration if you get stuck."
],
"challengeSeed": [
"// Example",
"var firstName = \"Ada\";",
"var lastLetterOfFirstName = firstName[firstName.length - 1];",
"",
"// Setup",
"var lastName = \"Lovelace\";",
"",
"// Only change code below this line.",
"var lastLetterOfLastName = lastName;",
"",
""
],
"tail": [
"(function(v){return v;})(lastLetterOfLastName);"
],
"solutions": [
"var firstName = \"Ada\";\nvar lastLetterOfFirstName = firstName[firstName.length - 1];\n\nvar lastName = \"Lovelace\";\nvar lastLetterOfLastName = lastName[lastName.length - 1];"
],
"tests": [
"assert(lastLetterOfLastName === \"e\", 'message: lastLetterOfLastName should be \"e\".');",
"assert(code.match(/\\.length/g).length === 2, 'message: You have to use .length to get the last letter.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Usa notación de corchetes para encontrar el último caracter de una cadena",
"descriptionEs": [
"Con el fin de conseguir la última letra de una cadena, puedes restar uno a la longitud de la cadena.",
"Por ejemplo, si var firstName = \"Charles\", se puede obtener la última letra usando firstName[firstName.length - 1]. ",
"Utiliza notación de corchetes para encontrar el último caracter de la variabel lastName.",
"Si te atascas intenta mirando la declaración de la variable lastLetterOfFirstName."
]
},
{
"id": "bd7123c9c452eddfaeb5bdef",
"title": "Use Bracket Notation to Find the Nth-to-Last Character in a String",
"description": [
"You can use the same principle we just used to retrieve the last character in a string to retrieve the Nth-to-last character.",
"For example, you can get the value of the third-to-last letter of the var firstName = \"Charles\" string by using firstName[firstName.length - 3]",
"
Instructions
",
"Use bracket notation to find the second-to-last character in the lastName string.",
" Hint Try looking at the thirdToLastLetterOfFirstName variable declaration if you get stuck."
],
"challengeSeed": [
"// Example",
"var firstName = \"Ada\";",
"var thirdToLastLetterOfFirstName = firstName[firstName.length - 3];",
"",
"// Setup",
"var lastName = \"Lovelace\";",
"",
"// Only change code below this line",
"var secondToLastLetterOfLastName = lastName;",
"",
""
],
"tail": [
"(function(v){return v;})(secondToLastLetterOfLastName);"
],
"solutions": [
"var firstName = \"Ada\";\nvar thirdToLastLetterOfFirstName = firstName[firstName.length - 3];\n\nvar lastName = \"Lovelace\";\nvar secondToLastLetterOfLastName = lastName[lastName.length - 2];"
],
"tests": [
"assert(secondToLastLetterOfLastName === 'c', 'message: secondToLastLetterOfLastName should be \"c\".');",
"assert(code.match(/\\.length/g).length === 2, 'message: You have to use .length to get the second last letter.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Usa notación de corchetes para encontrar el n-ésimo último caracter de una cadena",
"descriptionEs": [
"Puede utilizar el mismo principio utilizamos para recuperar el último caracter de una cadena para recuperar el n-ésimo último caracter.",
"Por ejemplo, se puede obtener el valor de la tercera última letra de la cadena var firstName = \"Charles\" utilizando firstName[firstName.length - 3] ",
"Usa notación de corchete para encontrar el segundo último caracter de la cadena en lastName.",
"Si te atascas intenta mirando la declaración de la variable thirdToLastLetterOfFirstName."
]
},
{
"id": "56533eb9ac21ba0edf2244bb",
"title": "Word Blanks",
"description": [
"We will now use our knowledge of strings to build a \"Mad Libs\" style word game we're calling \"Word Blanks\". You will create an (optionally humorous) \"Fill in the Blanks\" style sentence.",
"You will need to use string operators to build a new string, result, using the provided variables: myNoun, myAdjective, myVerb, and myAdverb.",
"You will also need to provide additional strings, which will not change, in between the provided words.",
"We have provided a framework for testing your results with different words. The tests will run your function with several different inputs to make sure all of the provided words appear in the output, as well as your extra strings."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function wordBlanks(myNoun, myAdjective, myVerb, myAdverb) {",
" var result = \"\";",
" // Your code below this line",
" ",
"",
" // Your code above this line",
" return result;",
"}",
"",
"// Change the words here to test your function",
"wordBlanks(\"dog\", \"big\", \"ran\", \"quickly\");"
],
"tail": [
"var test1 = wordBlanks(\"dog\", \"big\", \"ran\", \"quickly\");",
"var test2 = wordBlanks(\"cat\", \"little\", \"hit\", \"slowly\");"
],
"solutions": [
"function wordBlanks(myNoun, myAdjective, myVerb, myAdverb) {\n var result = \"\";\n\n result = \"Once there was a \" + myNoun + \" which was very \" + myAdjective + \". \";\n result += \"It \" + myVerb + \" \" + myAdverb + \" around the yard.\";\n\n return result;\n}"
],
"tests": [
"assert(typeof wordBlanks(\"\",\"\",\"\",\"\") === 'string', 'message: wordBlanks(\"\",\"\",\"\",\"\") should return a string.');",
"assert(/\\bdog\\b/.test(test1) && /\\bbig\\b/.test(test1) && /\\bran\\b/.test(test1) && /\\bquickly\\b/.test(test1),'message: wordBlanks(\"dog\", \"big\", \"ran\", \"quickly\") should contain all of the passed words separated by non-word characters (and any additional words in your madlib).');",
"assert(/\\bcat\\b/.test(test2) && /\\blittle\\b/.test(test2) && /\\bhit\\b/.test(test2) && /\\bslowly\\b/.test(test2),'message: wordBlanks(\"cat\", \"little\", \"hit\", \"slowly\") should contain all of the passed words separated by non-word characters (and any additional words in your madlib).');"
],
"type": "checkpoint",
"challengeType": 1
},
{
"id": "bd7993c9c69feddfaeb8bdef",
"title": "Store Multiple Values in one Variable using JavaScript Arrays",
"description": [
"With JavaScript array variables, we can store several pieces of data in one place.",
"You start an array declaration with an opening square bracket, end it with a closing square bracket, and put a comma between each entry, like this: var sandwich = [\"peanut butter\", \"jelly\", \"bread\"].",
"
Instructions
",
"Create a new array called myArray that contains both a string and a number (in that order).",
"Hint Refer to the example code in the text editor if you get stuck."
],
"challengeSeed": [
"// Example",
"var array = [\"John\", 23];",
"",
"// Only change code below this line.",
"var myArray = [];",
""
],
"tail": [
"(function(z){return z;})(myArray);"
],
"solutions": [
"var myArray = [\"The Answer\", 42];"
],
"tests": [
"assert(typeof myArray == 'object', 'message: myArray should be an array.');",
"assert(typeof myArray[0] !== 'undefined' && typeof myArray[0] == 'string', 'message: The first item in myArray should be a string.');",
"assert(typeof myArray[1] !== 'undefined' && typeof myArray[1] == 'number', 'message: The second item in myArray should be a number.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Almacena múltiples valores en una variable utilizando vectores en JavaScript",
"descriptionEs": [
"Con las variables tipo vector (o en inglés array) podemos almacenar diversos datos en un solo lugar.",
"Empiezas la declaración de un vector con un corchete de apertura, y terminas con un corchete de cierre, y pones una coma entre cada entrada, así: var sandwich = [\"mantequilla de maní\", \"jalea\" , \"pan\"]. ",
"Ahora vamos a crear un nuevo vector llamado myArray que contenga una cadena y un número (en ese orden).",
"Consulta el código comentado en el editor de texto si te atascas."
]
},
{
"id": "cf1111c1c11feddfaeb7bdef",
"title": "Nest one Array within Another Array",
"description": [
"You can also nest arrays within other arrays, like this: [[\"Bulls\", 23]]. This is also called a Multi-dimensional Array.",
"
Instructions
",
"Create a nested array called myArray."
],
"challengeSeed": [
"// Example",
"var ourArray = [[\"the universe\", \"everything\", 42]];",
"",
"// Only change code below this line.",
"var myArray = [];",
""
],
"tail": [
"if(typeof myArray !== \"undefined\"){(function(){return myArray;})();}"
],
"solutions": [
"var myArray = [[1,2,3]];"
],
"tests": [
"assert(Array.isArray(myArray) && myArray.some(Array.isArray), 'message: myArray should have at least one array nested within another array.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Anida un vector dentro de otro vector",
"descriptionEs": [
"También puedes anidar vectores dentro de otros vectores, como este: [[\"Bulls\", 23]].",
"Ahora vamos a crear un vector anidado llamado myArray."
]
},
{
"id": "bg9997c9c79feddfaeb9bdef",
"title": "Access Array Data with Indexes",
"description": [
"We can access the data inside arrays using indexes.",
"Array indexes are written in the same bracket notation that strings use, except that instead of specifying a character, they are specifying an entry in the array. Like strings, arrays use zero-based indexing, so the first element in an array is element 0.",
"Example",
"
var array = [1,2,3]; array[0]; // equals 1 var data = array[1]; // equals 2
",
"
Instructions
",
"Create a variable called myData and set it to equal the first value of myArray."
],
"challengeSeed": [
"// Example",
"var ourArray = [1,2,3];",
"var ourData = ourArray[0]; // equals 1",
"",
"// Setup",
"var myArray = [1,2,3];",
"",
"// Only change code below this line.",
""
],
"tail": [
"if(typeof myArray !== \"undefined\" && typeof myData !== \"undefined\"){(function(y,z){return 'myArray = ' + JSON.stringify(y) + ', myData = ' + JSON.stringify(z);})(myArray, myData);}"
],
"solutions": [
"var myArray = [1,2,3];\nvar myData = myArray[0];"
],
"tests": [
"assert((function(){if(typeof myArray != 'undefined' && typeof myData != 'undefined' && myArray[0] == myData){return true;}else{return false;}})(), 'message: The variable myData should equal the first value of myArray.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Accede a los datos de un vector mediante índices",
"descriptionEs": [
"Podemos acceder a los datos dentro de los vectores usando índices.",
"Los índices del vector se escriben en la misma notación con corchetes usado con cadenas, excepto que en lugar de especificar un caracter, especifican un elemento del vector.",
"Por ejemplo:",
"var array = [1,2,3];",
"array[0]; //es igual a 1",
"var data = array[1];",
"Crea una variable llamada myData y asignale el primer valor del vector myArray."
]
},
{
"id": "cf1111c1c11feddfaeb8bdef",
"title": "Modify Array Data With Indexes",
"description": [
"Unlike strings, the entries of arrays are mutable and can be changed freely.",
"Example",
"
var ourArray = [3,2,1]; ourArray[0] = 1; // equals [1,2,1]
",
"
Instructions
",
"Modify the data stored at index 0 of myArray to a value of 3."
],
"challengeSeed": [
"// Example",
"var ourArray = [1,2,3];",
"ourArray[1] = 3; // ourArray now equals [1,3,3].",
"",
"// Setup",
"var myArray = [1,2,3];",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"if(typeof myArray !== \"undefined\"){(function(){return myArray;})();}"
],
"solutions": [
"var myArray = [1,2,3];\nmyArray[0] = 3;"
],
"tests": [
"assert((function(){if(typeof myArray != 'undefined' && myArray[0] == 3 && myArray[1] == 2 && myArray[2] == 3){return true;}else{return false;}})(), 'message: myArray should now be [3,2,3].');",
"assert((function(){if(code.match(/myArray\\[0\\]\\s?=\\s?/g)){return true;}else{return false;}})(), 'message: You should be using correct index to modify the value in myArray.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Modifica datos de un vector usando índices",
"descriptionEs": [
"También podemos modificar los datos almacenados en vectores usando índices.",
"Por ejemplo:",
"var ourArray = [3,2,1];",
"ourArray[0] = 1; // equals [1,2,1]",
"Ahora establece el dato almacenado en el índice 0 de myArray para que sea el valor 3."
]
},
{
"id": "56592a60ddddeae28f7aa8e1",
"title": "Access Multi-Dimensional Arrays With Indexes",
"description": [
"One way to think of a multi-dimensional array, is as an array of arrays. When you use brackets to access your array, the first set of bracket refers to the entries in the outer-most array, and each subsequent level of brackets refers to the next level of entries inside.",
"Example",
"
",
"Read from myArray using bracket notation so that myData is equal to 8"
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var myArray = [[1,2,3], [4,5,6], [7,8,9], [[10,11,12], 13, 14]];",
"",
"// Only change code below this line.",
"var myData = myArray[0][0];",
""
],
"tail": [
"if(typeof myArray !== \"undefined\"){(function(){return \"myData: \" + myData + \" myArray: \" + JSON.stringify(myArray);})();}"
],
"solutions": [
"var myArray = [[1,2,3],[4,5,6], [7,8,9], [[10,11,12], 13, 14]];\nvar myData = myArray[2][1];"
],
"tests": [
"assert(myData === 8, 'message: myData should be equal to 8.');",
"assert(/myArray\\[2\\]\\[1\\]/g.test(code), 'message: You should be using bracket notation to read the value from myArray.');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "bg9995c9c69feddfaeb9bdef",
"title": "Manipulate Arrays With push()",
"description": [
"An easy way to append data to the end of an array is via the push() function.",
".push() takes one or more parameter and \"pushes\" it onto the end of the array.",
"
var arr = [1,2,3]; arr.push(4); // arr is now [1,2,3,4]
",
"
Instructions
",
"Push [\"dog\", 3] onto the end of the myArray variable."
],
"challengeSeed": [
"// Example",
"var ourArray = [\"Stimpson\", \"J\", \"cat\"];",
"ourArray.push([\"happy\", \"joy\"]); ",
"// ourArray now equals [\"Stimpson\", \"J\", \"cat\", [\"happy\", \"joy\"]]",
"",
"// Setup",
"var myArray = [[\"John\", 23], [\"cat\", 2]];",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"(function(z){return 'myArray = ' + JSON.stringify(z);})(myArray);"
],
"solutions": [
"var myArray = [[\"John\", 23], [\"cat\", 2]];\nmyArray.push([\"dog\",3]);"
],
"tests": [
"assert((function(d){if(d[2] != undefined && d[0][0] == 'John' && d[0][1] == 23 && d[2][0] == 'dog' && d[2][1] == 3 && d[2].length == 2){return true;}else{return false;}})(myArray), 'message: myArray should now equal [[\"John\", 23], [\"cat\", 2], [\"dog\", 3]].');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Manipula vectores con push()",
"descriptionEs": [
"No sólo se pueden sacar datos del final de un vector con pop(), también puedes empujar (push()) datos al final del vector.",
"Empuja [\"dog\", 3] al final de la variable myArray."
]
},
{
"id": "bg9994c9c69feddfaeb9bdef",
"title": "Manipulate Arrays With pop()",
"description": [
"Another way to change the data in an array is with the .pop() function.",
".pop() is used to \"pop\" a value off of the end of an array. We can store this \"popped off\" value by assigning it to a variable.",
"Any type of entry can be \"popped\" off of an array - numbers, strings, even nested arrays.",
"For example, for the code var oneDown = [1, 4, 6].pop(); the variable oneDown now holds the value 6 and the array becomes [1, 4].",
"
Instructions
",
"Use the .pop() function to remove the last item from myArray, assigning the \"popped off\" value to removedFromMyArray."
],
"challengeSeed": [
"// Example",
"var ourArray = [1,2,3];",
"var removedFromOurArray = ourArray.pop(); ",
"// removedFromOurArray now equals 3, and ourArray now equals [1,2]",
"",
"// Setup",
"var myArray = [[\"John\", 23], [\"cat\", 2]];",
"",
"// Only change code below this line.",
"var removedFromMyArray;",
"",
""
],
"tail": [
"(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);"
],
"solutions": [
"var myArray = [[\"John\", 23], [\"cat\", 2]];\nvar removedFromMyArray = myArray.pop();"
],
"tests": [
"assert((function(d){if(d[0][0] == 'John' && d[0][1] == 23 && d[2] == undefined){return true;}else{return false;}})(myArray), 'message: myArray should only contain [[\"John\", 23]].');",
"assert((function(d){if(d[0] == 'cat' && d[1] == 2 && d[2] == undefined){return true;}else{return false;}})(removedFromMyArray), 'message: removedFromMyArray should only contain [\"cat\", 2].');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Manipula vectores con pop()",
"descriptionEs": [
"Otra forma de cambiar los datos en un vector es con la función .pop().",
".pop() se utiliza para \"sacar\" el valor final de un vector. Podemos almacenar el valor \"sacado\" asignando pop a una variable por ejemplo durante su declaración.",
"Todo tipo de datos puede ser \"sacado\" de un vector --números, cadenas, incluso los vectores anidadas.",
"Usa la función .pop() para sacar el último elemento de myArray y asigna ese valor \"sacado\" a removedFromMyArray ."
]
},
{
"id": "bg9996c9c69feddfaeb9bdef",
"title": "Manipulate Arrays With shift()",
"description": [
"pop() always removes the last element of an array. What if you want to remove the first?",
"That's where .shift() comes in. It works just like .pop(), except it removes the first element instead of the last.",
"
Instructions
",
"Use the .shift() function to remove the first item from myArray, assigning the \"shifted off\" value to removedFromMyArray."
],
"challengeSeed": [
"// Example",
"var ourArray = [\"Stimpson\", \"J\", [\"cat\"]];",
"removedFromOurArray = ourArray.shift();",
"// removedFromOurArray now equals \"Stimpson\" and ourArray now equals [\"J\", [\"cat\"]].",
"",
"// Setup",
"var myArray = [[\"John\", 23], [\"dog\", 3]];",
"",
"// Only change code below this line.",
"var removedFromMyArray;",
"",
""
],
"tail": [
"(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);"
],
"solutions": [
"var myArray = [[\"John\", 23], [\"dog\", 3]];\n\n// Only change code below this line.\nvar removedFromMyArray = myArray.shift();"
],
"tests": [
"assert((function(d){if(d[0][0] == 'dog' && d[0][1] == 3 && d[1] == undefined){return true;}else{return false;}})(myArray), 'message: myArray should now equal [[\"dog\", 3]].');",
"assert((function(d){if(d[0] === 'John' && d[1] === 23 && typeof removedFromMyArray === 'object'){return true;}else{return false;}})(removedFromMyArray), 'message: removedFromMyArray should contain [\"John\", 23].');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Manipula vectores con shift()",
"descriptionEs": [
"pop() siempre elimina el último elemento de un vector. ¿Qué pasa si quieres quitar el primero?",
"Ahí es donde entra .shift(). Funciona igual que .pop (), excepto que elimina el primer elemento en lugar del pasado. ",
"Usa la función .shift() para eliminar el primer elemento de myArray, y el elemento que saques asignalo a removedFromMyArra"
]
},
{
"id": "bg9997c9c69feddfaeb9bdef",
"title": "Manipulate Arrays With unshift()",
"description": [
"Not only can you shift elements off of the beginning of an array, you can also unshift elements to the beginning of an array i.e. add elements in front of the array.",
".unshift() works exactly like .push(), but instead of adding the element at the end of the array, unshift() adds the element at the beginning of the array.",
"
Instructions
",
"Add [\"Paul\",35] to the beginning of the myArray variable using unshift()."
],
"challengeSeed": [
"// Example",
"var ourArray = [\"Stimpson\", \"J\", \"cat\"];",
"ourArray.shift(); // ourArray now equals [\"J\", \"cat\"]",
"ourArray.unshift(\"Happy\"); ",
"// ourArray now equals [\"Happy\", \"J\", \"cat\"]",
"",
"// Setup",
"var myArray = [[\"John\", 23], [\"dog\", 3]];",
"myArray.shift();",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"(function(y, z){return 'myArray = ' + JSON.stringify(y);})(myArray);"
],
"solutions": [
"var myArray = [[\"John\", 23], [\"dog\", 3]];\nmyArray.shift();\nmyArray.unshift([\"Paul\", 35]);"
],
"tests": [
"assert((function(d){if(typeof d[0] === \"object\" && d[0][0].toLowerCase() == 'paul' && d[0][1] == 35 && d[1][0] != undefined && d[1][0] == 'dog' && d[1][1] != undefined && d[1][1] == 3){return true;}else{return false;}})(myArray), 'message: myArray should now have [[\"Paul\", 35], [\"dog\", 3]].');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Manipula vectores con unshift()",
"descriptionEs": [
"No sólo se puedes correr (shift) elementos del comienzo de un vector, también puedes descorrerlos (unshift) al comienzo.",
"unshift() funciona exactamente igual que push(), pero en lugar de añadir el elemento al final del vector, unshift() añade el elemento al comienzo del vector. ",
"Añade \"Paul\" al comienzo de la variable myArray usando unshift()."
]
},
{
"id": "56533eb9ac21ba0edf2244bc",
"title": "Shopping List",
"description": [
"Create a shopping list in the variable myList. The list should be a multi-dimensional array containing several sub-arrays.",
"The first element in each sub-array should contain a string with the name of the item. The second element should be a number representing the quantity i.e.",
"[\"Chocolate Bar\", 15]",
"There should be at least 5 sub-arrays in the list."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var myList = [];",
"",
""
],
"tail": [
"var count = 0;",
"var isArray = false;",
"var hasString = false;",
"var hasNumber = false;",
"(function(list){",
" if(Array.isArray(myList)) {",
" isArray = true;",
" if(myList.length > 0) {",
" hasString = true;",
" hasNumber = true;",
" myList.forEach(function(elem) {",
" if(typeof elem[0] !== 'string') {",
" hasString = false;",
" }",
" if(typeof elem[1] !== 'number') {",
" hasNumber = false;",
" }",
" });",
" }",
" count = myList.length;",
" return JSON.stringify(myList);",
" } else {",
" return \"myList is not an array\";",
" }",
"",
"})(myList);"
],
"solutions": [
"var myList = [\n [\"Candy\", 10],\n [\"Potatoes\", 12],\n [\"Eggs\", 12],\n [\"Catfood\", 1],\n [\"Toads\", 9]\n];"
],
"tests": [
"assert(isArray, 'message: myList should be an array');",
"assert(hasString, 'message: The first elements in each of your sub-arrays must all be strings');",
"assert(hasNumber, 'message: The second elements in each of your sub-arrays must all be numbers');",
"assert(count > 4, 'message: You must have at least 5 items in your list');"
],
"type": "checkpoint",
"challengeType": 1
},
{
"id": "bg9997c9c89feddfaeb9bdef",
"title": "Write Reusable JavaScript with Functions",
"description": [
"In JavaScript, we can divide up our code into reusable parts called functions.",
"Here's an example of a function:",
"
function functionName() { console.log(\"Hello World\"); }
",
"You can call or invoke this function by using its name followed by parentheses, like this:",
"functionName();",
"Each time the function is called it will print out the message \"Hello World\" on the dev console. All of the code between the curly braces will be executed every time the function is called.",
"
Instructions
",
"
Create a function called myFunction which prints \"Hi World\" to the dev console.
Call the function.
"
],
"challengeSeed": [
"// Example",
"function ourFunction() {",
" console.log(\"Heyya, World\");",
"}",
"",
"ourFunction();",
"",
"// Only change code below this line",
"",
""
],
"tail": [
"var logOutput = \"\";",
"var oldLog = console.log;",
"function capture() {",
" console.log = function (message) {",
" logOutput = message.trim();",
" oldLog.apply(console, arguments);",
" };",
"}",
"",
"function uncapture() {",
" console.log = oldLog;",
"}",
"",
"if (typeof myFunction !== \"function\") { ",
" (function() { return \"myFunction is not defined\"; })();",
"} else {",
" capture();",
" myFunction(); ",
" uncapture();",
" (function() { return logOutput || \"console.log never called\"; })();",
"}"
],
"solutions": [
"function myFunction() {\n console.log(\"Hi World\");\n}\nmyFunction();"
],
"tests": [
"assert(typeof myFunction === 'function', 'message: myFunction should be a function');",
"assert(\"Hi World\" === logOutput, 'message: myFunction should output \"Hi World\" to the dev console');",
"assert(/^\\s*myFunction\\(\\)\\s*;/m.test(code), 'message: Call myFunction after you define it');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Escribe código Javascript reutilizable con funciones",
"descriptionEs": [
"En JavaScript, podemos dividir nuestro código en partes reutilizables llamadas funciones.",
"He aquí un ejemplo de una función:",
"function nombreDeFuncion(a, b) {",
"& nbsp; & nbsp; return a + b;",
"}",
"Después de escribir las líneas anteriores en nuestro código, podemos pasar valores a nuestra función y el resultado que sigue a la instrucción return será retornado.",
"Por ejemplo, podemos pasar los números 4 y 2 al \"llamar\" la función más adelante en nuestro código, así: nombreDeFuncion(4, 2). ",
"En este ejemplo, la función devolverá el número 6, ya que es el resultado de 4 + 2.",
"Crea y llama una función de nombre myFunction que devuelva la suma de a y b."
]
},
{
"id": "56533eb9ac21ba0edf2244bd",
"title": "Passing Values to Functions with Arguments",
"description": [
"Parameters are variables that act as placeholders for the values that are to be input to a function when it is called. When a function is defined, it is typically defined along with one or more parameters. The actual values that are input (or \"passed\") into a function when it is called are known as arguments.",
"Here is a function with two parameters, param1 and param2:",
"
function testFun(param1, param2) { console.log(param1, param2); }
",
"Then we can call testFun:",
"testFun(\"Hello\", \"World\");",
"We have passed two arguments, \"Hello\" and \"World\". Inside the function, param1 will equal \"Hello\" and param2 will equal \"World\". Note that you could call testFun again with different arguments and the parameters would take on the value of the new arguments.",
"
Instructions
",
"
Create a function called myFunction that accepts two arguments and outputs their sum to the dev console.
Call the function.
"
],
"releasedOn": "January 1, 2016",
"head": [
"var logOutput = \"\";",
"var oldLog = console.log;",
"function capture() {",
" console.log = function (message) {",
" logOutput = message + ''.trim();",
" oldLog.apply(console, arguments);",
" };",
"}",
"",
"function uncapture() {",
" console.log = oldLog;",
"}",
"",
"capture();"
],
"challengeSeed": [
"// Example",
"function ourFunction(a, b) {",
" console.log(a - b);",
"}",
"ourFunction(10, 5); // Outputs 5",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"uncapture();",
"",
"if (typeof myFunction !== \"function\") { ",
" (function() { return \"myFunction is not defined\"; })();",
"} else {",
" (function() { return logOutput || \"console.log never called\"; })();",
"}"
],
"solutions": [
"function myFunction(a, b) {\n console.log(a + b);\n}\nmyFunction(10, 5);"
],
"tests": [
"assert(typeof myFunction === 'function', 'message: myFunction should be a function');",
"if(typeof myFunction === \"function\") { capture(); myFunction(1,2); uncapture(); } assert(logOutput == 3, 'message: myFunction(1,2) should output 3');",
"if(typeof myFunction === \"function\") { capture(); myFunction(7,9); uncapture(); } assert(logOutput == 16, 'message: myFunction(7,9) should output 16');",
"assert(/^\\s*myFunction\\s*\\([\\w\\W]+\\)\\s*;/m.test(code), 'message: Call myFunction after you define it.');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244be",
"title": "Global Scope and Functions",
"description": [
"In JavaScript, scope refers to the visibility of variables. Variables which are defined outside of a function block have Global scope. This means, they can be seen everywhere in your JavaScript code.",
"Variables which are used without the var keyword are automatically created in the global scope. This can create unintended consequences elsewhere in your code or when running a function again. You should always declare your variables with var.",
"
Instructions
",
"Declare a global variable myGlobal outside of any function. Initialize it to have a value of 10 ",
"Inside function fun1, assign 5 to oopsGlobalwithout using the var keyword."
],
"releasedOn": "January 1, 2016",
"head": [
"var logOutput = \"\";",
"var oldLog = console.log;",
"function capture() {",
" console.log = function (message) {",
" logOutput = message;",
" oldLog.apply(console, arguments);",
" };",
"}",
"",
"function uncapture() {",
" console.log = oldLog;",
"}",
"var oopsGlobal;",
"capture();"
],
"challengeSeed": [
"// Declare your variable here",
"",
"",
"function fun1() {",
" // Assign 5 to oopsGlobal Here",
" ",
"}",
"",
"// Only change code above this line",
"function fun2() {",
" var output = \"\";",
" if (typeof myGlobal != \"undefined\") {",
" output += \"myGlobal: \" + myGlobal;",
" }",
" if (typeof oopsGlobal != \"undefined\") {",
" output += \" oopsGlobal: \" + oopsGlobal;",
" }",
" console.log(output);",
"}"
],
"tail": [
"fun1();",
"fun2();",
"uncapture();",
"(function() { return logOutput || \"console.log never called\"; })();"
],
"solutions": [
"// Declare your variable here\nvar myGlobal = 10;\n\nfunction fun1() {\n // Assign 5 to oopsGlobal Here\n oopsGlobal = 5;\n}\n\n// Only change code above this line\nfunction fun2() {\n var output = \"\";\n if(typeof myGlobal != \"undefined\") {\n output += \"myGlobal: \" + myGlobal;\n }\n if(typeof oopsGlobal != \"undefined\") {\n output += \" oopsGlobal: \" + oopsGlobal;\n }\n console.log(output);\n}"
],
"tests": [
"assert(typeof myGlobal != \"undefined\", 'message: myGlobal should be defined');",
"assert(myGlobal === 10, 'message: myGlobal should have a value of 10');",
"assert(/var\\s+myGlobal/.test(code), 'message: myGlobal should be declared using the var keyword');",
"assert(typeof oopsGlobal != \"undefined\" && oopsGlobal === 5, 'message: oopsGlobal should have a value of 5');",
"assert(!/var\\s+oopsGlobal/.test(code), 'message: Do not declare oopsGlobal using the var keyword');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244bf",
"title": "Local Scope and Functions",
"description": [
"Variables which are declared within a function, as well as the function parameters have local scope. That means, they are only visible within that function.",
"Here is a function myTest with a local variable called loc.",
"
function myTest() { var loc = \"foo\"; console.log(loc); } myTest(); // \"foo\" console.log(loc); // \"undefined\"
",
"loc is not defined outside of the function.",
"
Instructions
",
"Declare a local variable myVar inside myFunction"
],
"releasedOn": "January 1, 2016",
"head": [
"var logOutput = \"\";",
"var oldLog = console.log;",
"function capture() {",
" console.log = function (message) {",
" logOutput = message;",
" oldLog.apply(console, arguments);",
" };",
"}",
"",
"function uncapture() {",
" console.log = oldLog;",
"}",
""
],
"challengeSeed": [
"function myFunction() {",
" 'use strict';",
" ",
" ",
" console.log(myVar);",
"}",
"myFunction();",
"",
"// run and check the console ",
"// myVar is not defined outside of myFunction",
"console.log(myVar);",
"",
"// now remove the console log line to pass the test",
""
],
"tail": [
"typeof myFunction === 'function' && (capture(), myFunction(), uncapture());",
"(function() { return logOutput || \"console.log never called\"; })();"
],
"solutions": [
"function myFunction() {\n 'use strict';\n \n var myVar;\n console.log(myVar);\n}\nmyFunction();"
],
"tests": [
"assert(typeof myVar === 'undefined', 'message: No global myVar variable');",
"assert(/var\\s+myVar/.test(code), 'message: Add a local myVar variable');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244c0",
"title": "Global vs. Local Scope in Functions",
"description": [
"It is possible to have both local and global variables with the same name. When you do this, the local variable takes precedence over the global variable.",
"In this example:",
"
var someVar = \"Hat\"; function myFun() { var someVar = \"Head\"; return someVar; }
",
"The function myFun will return \"Head\" because the local version of the variable is present.",
"
Instructions
",
"Add a local variable to myFunction to override the value of outerWear with \"sweater\"."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var outerWear = \"T-Shirt\";",
"",
"function myFunction() {",
" // Only change code below this line",
" ",
" ",
" ",
" // Only change code above this line",
" return outerWear;",
"}",
"",
"myFunction();"
],
"solutions": [
"var outerWear = \"T-Shirt\";\nfunction myFunction() {\n var outerWear = \"sweater\";\n return outerWear;\n}"
],
"tests": [
"assert(outerWear === \"T-Shirt\", 'message: Do not change the value of the global outerWear');",
"assert(myFunction() === \"sweater\", 'message: myFunction should return \"sweater\"');",
"assert(/return outerWear/.test(code), 'message: Do not change the return statement');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244c2",
"title": "Return a Value from a Function with Return",
"description": [
"We can pass values into a function with arguments. You can use a return statement to send a value back out of a function.",
"Example",
"
function plusThree(num) { return num + 3; } var answer = plusThree(5); // 8
",
"plusThree takes an argument for num and returns a value equal to num + 3.",
"
Instructions
",
"Create a function timesFive that accepts one argument, multiplies it by 5, and returns the new value."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Example",
"function minusSeven(num) {",
" return num - 7;",
"}",
"",
"// Only change code below this line",
"",
""
],
"tail": [
"(function() { if(typeof timesFive === 'function'){ return \"timesfive(5) === \" + timesFive(5); } else { return \"timesFive is not a function\"} })();"
],
"solutions": [
"function timesFive(num) {\n return num * 5;\n}"
],
"tests": [
"assert(typeof timesFive === 'function', 'message: timesFive should be a function');",
"assert(timesFive(5) === 25, 'message: timesFive(5) should return 25');",
"assert(timesFive(2) === 10, 'message: timesFive(2) should return 10');",
"assert(timesFive(0) === 0, 'message: timesFive(0) should return 0');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244c3",
"title": "Assignment with a Returned Value",
"description": [
"If you'll recall from our discussion of Storing Values with the Equal Operator, everything to the right of the equal sign is resolved before the value is assigned. This means we can take the return value of a function and assign it to a variable.",
"Assume we have pre-defined a function sum which adds two numbers together, then: ",
"ourSum = sum(5, 12);",
"will call sum function, which returns a value of 17 and assigns it to ourSum variable.",
"
Instructions
",
"Call the process function with an argument of 7 and assign its return value to the variable processed."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Example",
"var changed = 0;",
"",
"function change(num) {",
" return (num + 5) / 3;",
"}",
"",
"changed = change(10);",
"",
"// Setup",
"var processed = 0;",
"",
"function process(num) {",
" return (num + 3) / 5;",
"}",
"",
"// Only change code below this line",
"",
""
],
"tail": [
"(function(){return \"processed = \" + processed})();"
],
"solutions": [
"var processed = 0;\n\nfunction process(num) {\n return (num + 3) / 5;\n}\n\nprocessed = process(7);"
],
"tests": [
"assert(processed === 2, 'message: processed should have a value of 2');",
"assert(/processed\\s*=\\s*process\\(\\s*7\\s*\\)\\s*;/.test(code), 'message: You should assign process to processed');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244c6",
"title": "Stand in Line",
"description": [
"In Computer Science a queue is an abstract Data Structure where items are kept in order. New items can be added at the back of the queue and old items are taken off from the front of the queue.",
"Write a function queue which takes an array (arr) and a number (item) as arguments. Add the number to the end of the array, then remove the first element of array. The queue function should then return the element that was removed."
],
"releasedOn": "January 1, 2016",
"head": [
"var logOutput = [];",
"var oldLog = console.log;",
"function capture() {",
" console.log = function (message) {",
" logOutput.push(message);",
" oldLog.apply(console, arguments);",
" };",
"}",
"",
"function uncapture() {",
" console.log = oldLog;",
"}",
"",
"capture();"
],
"challengeSeed": [
"function queue(arr, item) {",
" // Your code here",
" ",
" return item; // Change this line",
"}",
"",
"// Test Setup",
"var testArr = [1,2,3,4,5];",
"",
"// Display Code",
"console.log(\"Before: \" + JSON.stringify(testArr));",
"console.log(queue(testArr, 6)); // Modify this line to test",
"console.log(\"After: \" + JSON.stringify(testArr));"
],
"tail": [
"uncapture();",
"testArr = [1,2,3,4,5];",
"(function() { return logOutput.join(\"\\n\");})();"
],
"solutions": [
"var testArr = [ 1,2,3,4,5];\n\nfunction queue(arr, item) {\n arr.push(item);\n return arr.shift();\n}"
],
"tests": [
"assert(queue([],1) === 1, 'message: queue([], 1) should return 1');",
"assert(queue([2],1) === 2, 'message: queue([2], 1) should return 2');",
"assert(queue([5,6,7,8,9],1) === 5, 'message: queue([5,6,7,8,9], 1) should return 5');",
"queue(testArr, 10); assert(testArr[4] === 10, 'message: After queue(testArr, 10), myArr[4] should be 10');"
],
"type": "checkpoint",
"challengeType": 1
},
{
"id": "bd7123c9c441eddfaeb5bdef",
"title": "Understanding Boolean Values",
"description": [
"Another data type is the Boolean. Booleans may only be one of two values: true or false. They are basically little on-off switches, where true is \"on\" and false is \"off.\" These two states are mutually exclusive.",
"Note Boolean values are never written with quotes. The strings\"true\" and \"false\" are not Boolean and have no special meaning in JavaScript.",
"
Instructions
",
"Modify the welcomeToBooleans function so that it returns true instead of false when the run button is clicked."
],
"challengeSeed": [
"function welcomeToBooleans() {",
"",
"// Only change code below this line.",
"",
"return false; // Change this line",
"",
"// Only change code above this line.",
"}"
],
"tail": [
"welcomeToBooleans();"
],
"solutions": [
"function welcomeToBooleans() {\n return true; // Change this line\n}"
],
"tests": [
"assert(typeof welcomeToBooleans() === 'boolean', 'message: The welcomeToBooleans() function should return a boolean (true/false) value.');",
"assert(welcomeToBooleans() === true, 'message: welcomeToBooleans() should return true.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Entiende los valores booleanos",
"descriptionEs": [
"En informática las estructuras de datos son cosas que contienen datos. JavaScript tiene siete de estas. Por ejemplo, la estructura de datos Número contiene números. ",
"Vamos a aprender acerca de la estructura de datos más básica de todas: el Boolean. Los booleanos sólo puede contener el valor verdadero o el valor falso. Son básicamente pequeños interruptores de encendido y apagado. ",
"Vamos a modificar nuestra función welcomeToBooleans para que devuelva true en lugar de false cuando se pulse el botón de ejecución."
]
},
{
"id": "cf1111c1c12feddfaeb3bdef",
"title": "Use Conditional Logic with If Statements",
"description": [
"If statements are used to make decisions in code. The keyword if tells JavaScript to execute the code in the curly braces under certain conditions, defined in the parentheses. These conditions are known as Boolean conditions because they may only be true or false.",
"When the condition evaluates to true, the program executes the statement inside the curly braces. When the Boolean condition evaluates to false, the statement inside the curly braces will not execute.",
"Pseudocode",
"
if (condition is true) { statement is executed }
",
"Example",
"
function test (myCondition) { if (myCondition) { return \"It was true\"; } return \"It was false\"; } test(true); // returns \"It was true\" test(false); // returns \"It was false\"
",
"When test is called with a value of true, the if statement evaluates myCondition to see if it is true or not. Since it is true, the function returns \"It was true\". When we call test with a value of false, myCondition is nottrue and the statement in the curly braces is not executed and the function returns \"It was false\".",
"
Instructions
",
"Create an if statement inside the function to return \"That was true\" if the parameter wasThatTrue is true and return \"That was false\" otherwise."
],
"challengeSeed": [
"// Example",
"function ourFunction(isItTrue) {",
" if (isItTrue) { ",
" return \"Yes, it's true\";",
" }",
" return \"No, it's false\";",
"}",
"",
"// Setup",
"function myFunction(wasThatTrue) {",
"",
" // Only change code below this line.",
" ",
" ",
" ",
" // Only change code above this line.",
"",
"}",
"",
"// Change this value to test",
"myFunction(true);"
],
"solutions": [
"function myFunction(wasThatTrue) {\n if (wasThatTrue) {\n return \"That was true\";\n }\n return \"That was false\";\n}"
],
"tests": [
"assert(typeof myFunction === \"function\", 'message: myFunction should be a function');",
"assert(typeof myFunction(true) === \"string\", 'message: myFunction(true) should return a string');",
"assert(typeof myFunction(false) === \"string\", 'message: myFunction(false) should return a string');",
"assert(myFunction(true) === \"That was true\", 'message: myFunction(true) should return \"That was true\"');",
"assert(myFunction(false) === \"That was false\", 'message: myFunction(false) should return \"That was false\"');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Usa lógica condicional con instrucciones if y else",
"descriptionEs": [
"Podemos usar instrucciones if (\"if\" es \"si\" en español) en JavaScript para ejecutar código sólo cuando cierta condición se cumpla.",
"Las instrucciones if requieren evaluar algún tipo de condición booleana.",
"Por ejemplo:",
"if (1 === 2) {",
" return true;",
"} else {",
" return false;",
"}",
"Vamos a usar la instrucción if con else (\"else\" puede traducirse como \"de lo contrario\") para hacer un juego de cara o sello.",
"Crea una instrucción if con else que retorne la cadena \"heads\" si la variable flip es cero, o bien que retorne \"tails\" si la variable flip no es cero. "
]
},
{
"id": "56533eb9ac21ba0edf2244d0",
"title": "Comparison with the Equality Operator",
"description": [
"There are many Comparison Operators in JavaScript. All of these operators return a boolean true or false value.",
"The most basic operator is the equality operator ==. The equality operator compares two values and returns true if they're equivalent or false if they are not. Note that equality is different from assignment (=), which assigns the value at the right of the operator to a variable in the left.",
"
function equalityTest(myVal) { if (myVal == 10) { return \"Equal\"; } return \"Not Equal\"; }
",
"If myVal is equal to 10, the equality operator returns true, so the code in the curly braces will execute, and the function will return \"Equal\". Otherwise, the function will return \"Not Equal\".",
"In order for JavaScript to compare two different data types (for example, numbers and strings), it must convert one type to another. Once it does, however, it can compare terms as follows:",
"
",
"Add the equality operator to the indicated line so that the function will return \"Equal\" when val is equivalent to 12"
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"function myTest(val) {",
" if (val) { // Change this line",
" return \"Equal\";",
" }",
" return \"Not Equal\";",
"}",
"",
"// Change this value to test",
"myTest(10);"
],
"solutions": [
"function myTest(val) {\n if (val == 12) {\n return \"Equal\";\n }\n return \"Not Equal\";\n}"
],
"tests": [
"assert(myTest(10) === \"Not Equal\", 'message: myTest(10) should return \"Not Equal\"');",
"assert(myTest(12) === \"Equal\", 'message: myTest(12) should return \"Equal\"');",
"assert(myTest(\"12\") === \"Equal\", 'message: myTest(\"12\") should return \"Equal\"');",
"assert(code.match(/val\\s*==[\\s'\"\\d]+/g).length > 0, 'message: You should use the == operator');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d1",
"title": "Comparison with the Strict Equality Operator",
"description": [
"Strict equality (===) is the counterpart to the equality operator (==). Unlike the equality operator, strict equality tests both the data type and value of the compared elements.",
"Examples",
"
3 === 3 // true 3 === '3' // false
",
"In the second example, 3 is a Number type and '3' is a String type.",
"
Instructions
",
"Use strict equality operator in if statement so the function will return \"Equal\" when val is strictly equal to 7"
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"function myTest(val) {",
" if (val) { // Change this line",
" return \"Equal\";",
" }",
" return \"Not Equal\";",
"}",
"",
"// Change this value to test",
"myTest(10);"
],
"solutions": [
"function myTest(val) {\n if (val === 7) {\n return \"Equal\";\n }\n return \"Not Equal\";\n}"
],
"tests": [
"assert(myTest(10) === \"Not Equal\", 'message: myTest(10) should return \"Not Equal\"');",
"assert(myTest(7) === \"Equal\", 'message: myTest(7) should return \"Equal\"');",
"assert(myTest(\"7\") === \"Not Equal\", 'message: myTest(\"7\") should return \"Not Equal\"');",
"assert(code.match(/val\\s*===\\s*\\d+/g).length > 0, 'message: You should use the === operator');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d2",
"title": "Comparison with the Inequality Operator",
"description": [
"The inequality operator (!=) is the opposite of the equality operator. It means \"Not Equal\" and returns false where equality would return true and vice versa. Like the equality operator, the inequality operator will convert data types of values while comparing.",
"Examples",
"
",
"Add the inequality operator != in the if statement so that the function will return \"Not Equal\" when val is not equivalent to 99"
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"function myTest(val) {",
" if (val) { // Change this line",
" return \"Not Equal\";",
" }",
" return \"Equal\";",
"}",
"",
"// Change this value to test",
"myTest(10);"
],
"solutions": [
"function myTest(val) {\n if (val != 99) {\n return \"Not Equal\";\n }\n return \"Equal\";\n}"
],
"tests": [
"assert(myTest(99) === \"Equal\", 'message: myTest(99) should return \"Equal\"');",
"assert(myTest(\"99\") === \"Equal\", 'message: myTest(\"99\") should return \"Equal\"');",
"assert(myTest(12) === \"Not Equal\", 'message: myTest(12) should return \"Not Equal\"');",
"assert(myTest(\"12\") === \"Not Equal\", 'message: myTest(\"12\") should return \"Not Equal\"');",
"assert(myTest(\"bob\") === \"Not Equal\", 'message: myTest(\"bob\") should return \"Not Equal\"');",
"assert(code.match(/val\\s*!=\\s*\\d+/g).length > 0, 'message: You should use the != operator');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d3",
"title": "Comparison with the Strict Inequality Operator",
"description": [
"The strict inequality operator (!==) is the opposite of the strict equality operator. It means \"Strictly Not Equal\" and returns false where strict equality would return true and vice versa. Strict inequality will not convert data types.",
"Examples",
"
",
"Add the strict inequality operator to the if statement so the function will return \"Not Equal\" when val is not strictly equal to 17"
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"function myTest(val) {",
" // Only Change Code Below this Line",
" ",
" if (val) {",
"",
" // Only Change Code Above this Line",
"",
" return \"Not Equal\";",
" }",
" return \"Equal\";",
"}",
"",
"// Change this value to test",
"myTest(10);"
],
"solutions": [
"function myTest(val) {\n if (val !== 17) {\n return \"Not Equal\";\n }\n return \"Equal\";\n}"
],
"tests": [
"assert(myTest(17) === \"Equal\", 'message: myTest(17) should return \"Equal\"');",
"assert(myTest(\"17\") === \"Not Equal\", 'message: myTest(\"17\") should return \"Not Equal\"');",
"assert(myTest(12) === \"Not Equal\", 'message: myTest(12) should return \"Not Equal\"');",
"assert(myTest(\"bob\") === \"Not Equal\", 'message: myTest(\"bob\") should return \"Not Equal\"');",
"assert(code.match(/val\\s*!==\\s*\\d+/g).length > 0, 'message: You should use the !== operator');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d4",
"title": "Comparison with the Greater Than Operator",
"description": [
"The greater than operator (>) compares the values of two numbers. If the number to the left is greater than the number to the right, it returns true. Otherwise, it returns false.",
"Like the equality operator, greater than operator will convert data types of values while comparing.",
"Examples",
"
",
"Add the greater than operator to the indicated lines so that the return statements make sense."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" if (val) { // Change this line",
" return \"Over 100\";",
" }",
" ",
" if (val) { // Change this line",
" return \"Over 10\";",
" }",
"",
" return \"10 or Under\";",
"}",
"",
"// Change this value to test",
"myTest(10);"
],
"solutions": [
"function myTest(val) {\n if (val > 100) { // Change this line\n return \"Over 100\";\n }\n if (val > 10) { // Change this line\n return \"Over 10\";\n }\n return \"10 or Under\";\n}"
],
"tests": [
"assert(myTest(0) === \"10 or Under\", 'message: myTest(0) should return \"10 or Under\"');",
"assert(myTest(10) === \"10 or Under\", 'message: myTest(10) should return \"10 or Under\"');",
"assert(myTest(11) === \"Over 10\", 'message: myTest(11) should return \"Over 10\"');",
"assert(myTest(99) === \"Over 10\", 'message: myTest(99) should return \"Over 10\"');",
"assert(myTest(100) === \"Over 10\", 'message: myTest(100) should return \"Over 10\"');",
"assert(myTest(101) === \"Over 100\", 'message: myTest(101) should return \"Over 100\"');",
"assert(myTest(150) === \"Over 100\", 'message: myTest(150) should return \"Over 100\"');",
"assert(code.match(/val\\s*>\\s*('|\")*\\d+('|\")*/g).length > 1, 'message: You should use the > operator at least twice');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d5",
"title": "Comparison with the Greater Than Or Equal To Operator",
"description": [
"The greater than or equal to operator (>=) compares the values of two numbers. If the number to the left is greater than or equal to the number to the right, it returns true. Otherwise, it returns false.",
"Like the equality operator, greater than or equal to operator will convert data types while comparing.",
"Examples",
"
",
"Add the greater than or equal to operator to the indicated lines so that the return statements make sense."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" if (val) { // Change this line",
" return \"20 or Over\";",
" }",
" ",
" if (val) { // Change this line",
" return \"10 or Over\";",
" }",
"",
" return \"9 or Under\";",
"}",
"",
"// Change this value to test",
"myTest(10);"
],
"solutions": [
"function myTest(val) {\n if (val >= 20) { // Change this line\n return \"20 or Over\";\n }\n \n if (val >= 10) { // Change this line\n return \"10 or Over\";\n }\n\n return \"9 or Under\";\n}"
],
"tests": [
"assert(myTest(0) === \"9 or Under\", 'message: myTest(0) should return \"9 or Under\"');",
"assert(myTest(9) === \"9 or Under\", 'message: myTest(9) should return \"9 or Under\"');",
"assert(myTest(10) === \"10 or Over\", 'message: myTest(10) should return \"10 or Over\"');",
"assert(myTest(11) === \"10 or Over\", 'message: myTest(11) should return \"10 or Over\"');",
"assert(myTest(19) === \"10 or Over\", 'message: myTest(19) should return \"10 or Over\"');",
"assert(myTest(100) === \"20 or Over\", 'message: myTest(100) should return \"20 or Over\"');",
"assert(myTest(21) === \"20 or Over\", 'message: myTest(21) should return \"20 or Over\"');",
"assert(code.match(/val\\s*>=\\s*('|\")*\\d+('|\")*/g).length > 1, 'message: You should use the >= operator at least twice');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d6",
"title": "Comparison with the Less Than Operator",
"description": [
"The less than operator (<) compares the values of two numbers. If the number to the left is less than the number to the right, it returns true. Otherwise, it returns false. Like the equality operator, less than operator converts data types while comparing.",
"Examples",
"
",
"Add the less than operator to the indicated lines so that the return statements make sense."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" if (val) { // Change this line",
" return \"Under 25\";",
" }",
" ",
" if (val) { // Change this line",
" return \"Under 55\";",
" }",
"",
" return \"55 or Over\";",
"}",
"",
"// Change this value to test",
"myTest(10);"
],
"solutions": [
"function myTest(val) {\n if (val < 25) { // Change this line\n return \"Under 25\";\n }\n \n if (val < 55) { // Change this line\n return \"Under 55\";\n }\n\n return \"55 or Over\";\n}"
],
"tests": [
"assert(myTest(0) === \"Under 25\", 'message: myTest(0) should return \"Under 25\"');",
"assert(myTest(24) === \"Under 25\", 'message: myTest(24) should return \"Under 25\"');",
"assert(myTest(25) === \"Under 55\", 'message: myTest(25) should return \"Under 55\"');",
"assert(myTest(54) === \"Under 55\", 'message: myTest(54) should return \"Under 55\"');",
"assert(myTest(55) === \"55 or Over\", 'message: myTest(55) should return \"55 or Over\"');",
"assert(myTest(99) === \"55 or Over\", 'message: myTest(99) should return \"55 or Over\"');",
"assert(code.match(/val\\s*<\\s*('|\")*\\d+('|\")*/g).length > 1, 'message: You should use the < operator at least twice');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d7",
"title": "Comparison with the Less Than Or Equal To Operator",
"description": [
"The less than or equal to operator (<=) compares the values of two numbers. If the number to the left is less than or equal the number to the right, it returns true. If the number on the left is greater than the number on the right, it returns false. Like the equality operator, less than or equal to converts data types.",
"Examples",
"
",
"Add the less than or equal to operator to the indicated lines so that the return statements make sense."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" if (val) { // Change this line",
" return \"Smaller Than or Equal to 12\";",
" }",
" ",
" if (val) { // Change this line",
" return \"Smaller Than or Equal to 24\";",
" }",
"",
" return \"25 or More\";",
"}",
"",
"// Change this value to test",
"myTest(10);",
""
],
"solutions": [
"function myTest(val) {\n if (val <= 12) { // Change this line\n return \"Smaller Than or Equal to 12\";\n }\n \n if (val <= 24) { // Change this line\n return \"Smaller Than or Equal to 24\";\n }\n\n return \"25 or More\";\n}"
],
"tests": [
"assert(myTest(0) === \"Smaller Than or Equal to 12\", 'message: myTest(0) should return \"Smaller Than or Equal to 12\"');",
"assert(myTest(11) === \"Smaller Than or Equal to 12\", 'message: myTest(11) should return \"Smaller Than or Equal to 12\"');",
"assert(myTest(12) === \"Smaller Than or Equal to 12\", 'message: myTest(12) should return \"Smaller Than or Equal to 12\"');",
"assert(myTest(23) === \"Smaller Than or Equal to 24\", 'message: myTest(23) should return \"Smaller Than or Equal to 24\"');",
"assert(myTest(24) === \"Smaller Than or Equal to 24\", 'message: myTest(24) should return \"Smaller Than or Equal to 24\"');",
"assert(myTest(25) === \"25 or More\", 'message: myTest(25) should return \"25 or More\"');",
"assert(myTest(55) === \"25 or More\", 'message: myTest(55) should return \"25 or More\"');",
"assert(code.match(/val\\s*<=\\s*('|\")*\\d+('|\")*/g).length > 1, 'message: You should use the <= operator at least twice');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d8",
"title": "Comparisons with the Logical And Operator",
"description": [
"Sometimes you will need to test more than one thing at a time. The logical and operator (&&) returns true if and only if the operands to the left and right of it are true.",
"The same effect could be achieved by nesting an if statement inside another if:",
"
if (num > 5) { if (num < 10) { return \"Yes\"; } } return \"No\";
",
"will only return \"Yes\" if num is between 6 and 9 (6 and 9 included). The same logic can be written as:",
"
if (num > 5 && num < 10) { return \"Yes\"; } return \"No\";
",
"
Instructions
",
"Combine the two if statements into one statement which will return \"Yes\" if val is less than or equal to 50 and greater than or equal to 25. Otherwise, will return \"No\"."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" // Only change code below this line",
"",
" if (val) {",
" if (val) {",
" return \"Yes\";",
" }",
" }",
"",
" // Only change code above this line",
" return \"No\";",
"}",
"",
"// Change this value to test",
"myTest(10);"
],
"solutions": [
"function myTest(val) {\n if (val >= 25 && val <= 50) {\n return \"Yes\";\n }\n return \"No\";\n}"
],
"tests": [
"assert(code.match(/&&/g).length === 1, 'message: You should use the && operator once');",
"assert(code.match(/if/g).length === 1, 'message: You should only have one if statement');",
"assert(myTest(0) === \"No\", 'message: myTest(0) should return \"No\"');",
"assert(myTest(24) === \"No\", 'message: myTest(24) should return \"No\"');",
"assert(myTest(25) === \"Yes\", 'message: myTest(25) should return \"Yes\"');",
"assert(myTest(30) === \"Yes\", 'message: myTest(30) should return \"Yes\"');",
"assert(myTest(50) === \"Yes\", 'message: myTest(50) should return \"Yes\"');",
"assert(myTest(51) === \"No\", 'message: myTest(51) should return \"No\"');",
"assert(myTest(75) === \"No\", 'message: myTest(75) should return \"No\"');",
"assert(myTest(51) === \"No\", 'message: myTest(51) should return \"No\"');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244d9",
"title": "Comparisons with the Logical Or Operator",
"description": [
"The logical or operator (||) returns true if either of the operands is true. Otherwise, it returns false.",
"The pattern below should look familiar from prior waypoints:",
"
if (num > 10) { return \"No\"; } if (num < 5) { return \"No\"; } return \"Yes\";
",
"will return \"Yes\" only if num is between 5 and 10 (5 and 10 included). The same logic can be written as:",
"
if (num > 10 || num < 5) { return \"No\"; } return \"Yes\";
",
"
Instructions
",
"Combine the two if statements into one statement which returns \"Outside\" if val is not between 10 and 20, inclusive. Otherwise, return \"Inside\"."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" // Only change code below this line",
"",
" if (val) {",
" return \"Outside\";",
" }",
"",
" if (val) {",
" return \"Outside\";",
" }",
"",
" // Only change code above this line",
" return \"Inside\";",
"}",
"",
"// Change this value to test",
"myTest(15);"
],
"solutions": [
"function myTest(val) {\n if (val < 10 || val > 20) {\n return \"Outside\";\n }\n return \"Inside\";\n}"
],
"tests": [
"assert(code.match(/\\|\\|/g).length === 1, 'message: You should use the || operator once');",
"assert(code.match(/if/g).length === 1, 'message: You should only have one if statement');",
"assert(myTest(0) === \"Outside\", 'message: myTest(0) should return \"Outside\"');",
"assert(myTest(9) === \"Outside\", 'message: myTest(9) should return \"Outside\"');",
"assert(myTest(10) === \"Inside\", 'message: myTest(10) should return \"Inside\"');",
"assert(myTest(15) === \"Inside\", 'message: myTest(15) should return \"Inside\"');",
"assert(myTest(19) === \"Inside\", 'message: myTest(19) should return \"Inside\"');",
"assert(myTest(20) === \"Inside\", 'message: myTest(20) should return \"Inside\"');",
"assert(myTest(21) === \"Outside\", 'message: myTest(21) should return \"Outside\"');",
"assert(myTest(25) === \"Outside\", 'message: myTest(25) should return \"Outside\"');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244da",
"title": "Introducing Else Statements",
"description": [
"When a condition for an if statement is true, the block of code following it is executed. What about when that condition is false? Normally nothing would happen. With an else statement, an alternate block of code can be executed.",
"
if (num > 10) { return \"Bigger than 10\"; } else { return \"10 or Less\"; }
",
"
Instructions
",
"Combine the if statements into a single if/else statement."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" var result = \"\";",
" // Only change code below this line",
" ",
" if (val > 5) {",
" result = \"Bigger than 5\";",
" }",
" ",
" if (val <= 5) {",
" result = \"5 or Smaller\";",
" }",
" ",
" // Only change code above this line",
" return result;",
"}",
"",
"// Change this value to test",
"myTest(4);",
""
],
"solutions": [
"function myTest(val) {\n var result = \"\";\n if(val > 5) {\n result = \"Bigger than 5\";\n } else {\n result = \"5 or Smaller\";\n }\n return result;\n}"
],
"tests": [
"assert(code.match(/if/g).length === 1, 'message: You should only have one if statement');",
"assert(/else/g.test(code), 'message: You should use an else statement');",
"assert(myTest(4) === \"5 or Smaller\", 'message: myTest(4) should return \"5 or Smaller\"');",
"assert(myTest(5) === \"5 or Smaller\", 'message: myTest(5) should return \"5 or Smaller\"');",
"assert(myTest(6) === \"Bigger than 5\", 'message: myTest(6) should return \"Bigger than 5\"');",
"assert(myTest(10) === \"Bigger than 5\", 'message: myTest(10) should return \"Bigger than 5\"');",
"assert(/var result = \"\";/.test(code) && /return result;/.test(code), 'message: Do not change the code above or below the lines.');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244db",
"title": "Introducing Else If Statements",
"description": [
"If you have multiple conditions that need to be addressed, you can chain if statements together with else if statements.",
"
if (num > 15) { return \"Bigger than 15\"; } else if (num < 5) { return \"Smaller than 5\"; } else { return \"Between 5 and 15\"; }
",
"
Instructions
",
"Convert the logic to use else if statements."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" if (val > 10) {",
" return \"Greater than 10\";",
" }",
" ",
" if (val < 5) {",
" return \"Smaller than 5\";",
" }",
" ",
" return \"Between 5 and 10\";",
"}",
"",
"// Change this value to test",
"myTest(7);",
""
],
"solutions": [
"function myTest(val) {\n if(val > 10) {\n return \"Greater than 10\";\n } else if(val < 5) {\n return \"Smaller than 5\";\n } else {\n return \"Between 5 and 10\";\n }\n}"
],
"tests": [
"assert(code.match(/else/g).length > 1, 'message: You should have at least two else statements');",
"assert(code.match(/if/g).length > 1, 'message: You should have at least two if statements');",
"assert(myTest(0) === \"Smaller than 5\", 'message: myTest(0) should return \"Smaller than 5\"');",
"assert(myTest(5) === \"Between 5 and 10\", 'message: myTest(5) should return \"Between 5 and 10\"');",
"assert(myTest(7) === \"Between 5 and 10\", 'message: myTest(7) should return \"Between 5 and 10\"');",
"assert(myTest(10) === \"Between 5 and 10\", 'message: myTest(10) should return \"Between 5 and 10\"');",
"assert(myTest(12) === \"Greater than 10\", 'message: myTest(12) should return \"Greater than 10\"');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "5690307fddb111c6084545d7",
"title": "Logical Order in If Else Statements",
"description": [
"Order is important in if, else if statements.",
"The loop is executed from top to bottom so you will want to be careful of what statement comes first.",
"Take these two functions as an example.",
"Heres the first:",
"
function foo(x) { if (x < 1) { return \"Less than one\"; } else if (x < 2) { return \"Less than two\"; } else { return \"Greater than or equal to two\"; } }
",
"And the second just switches the order of the statements:",
"
function bar(x) { if (x < 2) { return \"Less than two\"; } else if (x < 1) { return \"Less than one\"; } else { return \"Greater than or equal to two\"; } }
",
"While these two functions look nearly identical if we pass a number to both we get different outputs.",
"
foo(0) // \"Less than one\" bar(0) // \"Less than two\"
",
"
Instructions
",
"Change the order of logic in the function so that it will return the correct statements in all cases."
],
"challengeSeed": [
"function myTest(val) {",
" if (val < 10) {",
" return \"Less than 10\";",
" } else if (val < 5) {",
" return \"Less than 5\";",
" } else {",
" return \"Greater than or equal to 10\";",
" }",
"}",
"",
"// Change this value to test",
"myTest(7);"
],
"solutions": [
"function myTest(val) {\n if(val < 5) {\n return \"Less than 5\"; \n } else if (val < 10) {\n return \"Less than 10\";\n } else {\n return \"Greater than or equal to 10\";\n }\n}"
],
"tests": [
"assert(myTest(4) === \"Less than 5\", 'message: myTest(4) should return \"Less than 5\"');",
"assert(myTest(6) === \"Less than 10\", 'message: myTest(6) should return \"Less than 10\"');",
"assert(myTest(11) === \"Greater than or equal to 10\", 'message: myTest(11) should return \"Greater than or equal to 10\"');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244dc",
"title": "Chaining If Else Statements",
"description": [
"if/else statements can be chained together for complex logic. Here is pseudocode of multiple chained if / else if statements:",
"
if (condition1) { statement1 } else if (condition2) { statement2 } else if (condition3) { statement3 . . . } else { statementN }
",
"
Instructions
",
"Write chained if/else if statements to fulfill the following conditions:",
"num < 5 - return \"Tiny\" num < 10 - return \"Small\" num < 15 - return \"Medium\" num < 20 - return \"Large\" num >= 20 - return \"Huge\""
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(num) {",
" // Only change code below this line",
" ",
" ",
" return \"Change Me\";",
" // Only change code above this line",
"}",
"",
"// Change this value to test",
"myTest(7);"
],
"solutions": [
"function myTest(num) {\n if (num < 5) {\n return \"Tiny\";\n } else if (num < 10) {\n return \"Small\";\n } else if (num < 15) {\n return \"Medium\";\n } else if (num < 20) {\n return \"Large\";\n } else {\n return \"Huge\";\n }\n}"
],
"tests": [
"assert(code.match(/else/g).length > 3, 'message: You should have at least four else statements');",
"assert(code.match(/if/g).length > 3, 'message: You should have at least four if statements');",
"assert(code.match(/return/g).length >= 5, 'message: You should have at least five return statements');",
"assert(myTest(0) === \"Tiny\", 'message: myTest(0) should return \"Tiny\"');",
"assert(myTest(4) === \"Tiny\", 'message: myTest(4) should return \"Tiny\"');",
"assert(myTest(5) === \"Small\", 'message: myTest(5) should return \"Small\"');",
"assert(myTest(8) === \"Small\", 'message: myTest(8) should return \"Small\"');",
"assert(myTest(10) === \"Medium\", 'message: myTest(10) should return \"Medium\"');",
"assert(myTest(14) === \"Medium\", 'message: myTest(14) should return \"Medium\"');",
"assert(myTest(15) === \"Large\", 'message: myTest(15) should return \"Large\"');",
"assert(myTest(17) === \"Large\", 'message: myTest(17) should return \"Large\"');",
"assert(myTest(20) === \"Huge\", 'message: myTest(20) should return \"Huge\"');",
"assert(myTest(25) === \"Huge\", 'message: myTest(25) should return \"Huge\"');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "5664820f61c48e80c9fa476c",
"title": "Golf Code",
"description": [
"In the game of golf each hole has a par for the average number of strokes needed to sink the ball. Depending on how far above or below par your strokes are, there is a different nickname.",
"Your function will be passed a par and strokes. Return strings according to this table (based on order of priority - top (highest) to bottom (lowest)):",
"
Strokes
Return
1
\"Hole-in-one!\"
<= par - 2
\"Eagle\"
par - 1
\"Birdie\"
par
\"Par\"
par + 1
\"Bogey\"
par + 2
\"Double Bogey\"
>= par + 3
\"Go Home!\"
",
"par and strokes will always be numeric and positive."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function golfScore(par, strokes) {",
" // Only change code below this line",
" ",
" ",
" return \"Change Me\";",
" // Only change code above this line",
"}",
"",
"// Change these values to test",
"golfScore(5, 4);"
],
"solutions": [
"function golfScore(par, strokes) {\n if (strokes === 1) {\n return \"Hole-in-one!\";\n }\n \n if (strokes <= par - 2) {\n return \"Eagle\";\n }\n \n if (strokes === par - 1) {\n return \"Birdie\";\n }\n \n if (strokes === par) {\n return \"Par\";\n }\n \n if (strokes === par + 1) {\n return \"Bogey\";\n }\n \n if(strokes === par + 2) {\n return \"Double Bogey\";\n }\n \n return \"Go Home!\";\n}"
],
"tests": [
"assert(golfScore(4, 1) === \"Hole-in-one!\", 'message: golfScore(4, 1) should return \"Hole-in-one!\"');",
"assert(golfScore(4, 2) === \"Eagle\", 'message: golfScore(4, 2) should return \"Eagle\"');",
"assert(golfScore(5, 2) === \"Eagle\", 'message: golfScore(5, 2) should return \"Eagle\"');",
"assert(golfScore(4, 3) === \"Birdie\", 'message: golfScore(4, 3) should return \"Birdie\"');",
"assert(golfScore(4, 4) === \"Par\", 'message: golfScore(4, 4) should return \"Par\"');",
"assert(golfScore(1, 1) === \"Hole-in-one!\", 'message: golfScore(1, 1) should return \"Hole-in-one!\"');",
"assert(golfScore(5, 5) === \"Par\", 'message: golfScore(5, 5) should return \"Par\"');",
"assert(golfScore(4, 5) === \"Bogey\", 'message: golfScore(4, 5) should return \"Bogey\"');",
"assert(golfScore(4, 6) === \"Double Bogey\", 'message: golfScore(4, 6) should return \"Double Bogey\"');",
"assert(golfScore(4, 7) === \"Go Home!\", 'message: golfScore(4, 7) should return \"Go Home!\"');",
"assert(golfScore(5, 9) === \"Go Home!\", 'message: golfScore(5, 9) should return \"Go Home!\"');"
],
"type": "checkpoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244dd",
"title": "Selecting from many options with Switch Statements",
"description": [
"If you have many options to choose from, use a switch statement. A switch statement tests a value and can have many case statements which defines various possible values. Statements are executed from the first matched case value until a break is encountered.",
"Here is a pseudocode example:",
"
switch (num) { case value1: statement1; break; case value2: statement2; break; ... case valueN: statementN; break; }
",
"case values are tested with strict equality (===). The break tells JavaScript to stop executing statements. If the break is omitted, the next statement will be executed.",
"
Instructions
",
"Write a switch statement which tests val and sets answer for the following conditions: 1 - \"alpha\" 2 - \"beta\" 3 - \"gamma\" 4 - \"delta\""
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" var answer = \"\";",
" // Only change code below this line",
" ",
" ",
" ",
" // Only change code above this line ",
" return answer; ",
"}",
"",
"// Change this value to test",
"myTest(1);",
""
],
"solutions": [
"function myTest(val) {\n var answer = \"\";\n\n switch (val) {\n case 1:\n answer = \"alpha\";\n break;\n case 2:\n answer = \"beta\";\n break;\n case 3:\n answer = \"gamma\";\n break;\n case 4:\n answer = \"delta\";\n }\n return answer; \n}"
],
"tests": [
"assert(myTest(1) === \"alpha\", 'message: myTest(1) should have a value of \"alpha\"');",
"assert(myTest(2) === \"beta\", 'message: myTest(2) should have a value of \"beta\"');",
"assert(myTest(3) === \"gamma\", 'message: myTest(3) should have a value of \"gamma\"');",
"assert(myTest(4) === \"delta\", 'message: myTest(4) should have a value of \"delta\"');",
"assert(!/else/g.test(code) || !/if/g.test(code), 'message: You should not use any if or else statements');",
"assert(code.match(/break/g).length > 2, 'message: You should have at least 3 break statements');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244de",
"title": "Adding a default option in Switch statements",
"description": [
"In a switch statement you may not be able to specify all possible values as case statements. Instead, you can add the default statement which will be executed if no matching case statements are found. Think of it like the final else statement in an if/else chain.",
"A default statement should be the last case.",
"
switch (num) { case value1: statement1; break; case value2: statement2; break; ... default: defaultStatement; }
",
"
Instructions
",
"Write a switch statement to set answer for the following conditions: \"a\" - \"apple\" \"b\" - \"bird\" \"c\" - \"cat\" default - \"stuff\""
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" var answer = \"\";",
" // Only change code below this line",
" ",
" ",
" ",
" // Only change code above this line ",
" return answer; ",
"}",
"",
"// Change this value to test",
"myTest(1);",
""
],
"solutions": [
"function myTest(val) {\n var answer = \"\";\n\n switch(val) {\n case \"a\":\n answer = \"apple\";\n break;\n case \"b\":\n answer = \"bird\";\n break;\n case \"c\":\n answer = \"cat\";\n break;\n default:\n answer = \"stuff\";\n }\n return answer; \n}"
],
"tests": [
"assert(myTest(\"a\") === \"apple\", 'message: myTest(\"a\") should have a value of \"apple\"');",
"assert(myTest(\"b\") === \"bird\", 'message: myTest(\"b\") should have a value of \"bird\"');",
"assert(myTest(\"c\") === \"cat\", 'message: myTest(\"c\") should have a value of \"cat\"');",
"assert(myTest(\"d\") === \"stuff\", 'message: myTest(\"d\") should have a value of \"stuff\"');",
"assert(myTest(4) === \"stuff\", 'message: myTest(4) should have a value of \"stuff\"');",
"assert(!/else/g.test(code) || !/if/g.test(code), 'message: You should not use any if or else statements');",
"assert(code.match(/break/g).length > 2, 'message: You should have at least 3 break statements');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244df",
"title": "Multiple Identical Options in Switch Statements",
"description": [
"If the break statement is omitted from a switch statement's case, the following case statement(s) are executed until a break is encountered. If you have multiple inputs with the same output, you can represent them in a switch statement like this:",
"
switch(val) { case 1: case 2: case 3: result = \"1, 2, or 3\"; break; case 4: result = \"4 alone\"; }
",
"Cases for 1, 2, and 3 will all produce the same result.",
"
Instructions
",
"Write a switch statement to set answer for the following ranges: 1-3 - \"Low\" 4-6 - \"Mid\" 7-9 - \"High\"",
"Note You will need to have a case statement for each number in the range."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" var answer = \"\";",
" // Only change code below this line",
" ",
" ",
" ",
" // Only change code above this line ",
" return answer; ",
"}",
"",
"// Change this value to test",
"myTest(1);",
""
],
"solutions": [
"function myTest(val) {\n var answer = \"\";\n \n switch (val) {\n case 1:\n case 2:\n case 3:\n answer = \"Low\";\n break;\n case 4:\n case 5:\n case 6:\n answer = \"Mid\";\n break;\n case 7:\n case 8:\n case 9:\n answer = \"High\";\n }\n \n return answer; \n}"
],
"tests": [
"assert(myTest(1) === \"Low\", 'message: myTest(1) should return \"Low\"');",
"assert(myTest(2) === \"Low\", 'message: myTest(2) should return \"Low\"');",
"assert(myTest(3) === \"Low\", 'message: myTest(3) should return \"Low\"');",
"assert(myTest(4) === \"Mid\", 'message: myTest(4) should return \"Mid\"');",
"assert(myTest(5) === \"Mid\", 'message: myTest(5) should return \"Mid\"');",
"assert(myTest(6) === \"Mid\", 'message: myTest(6) should return \"Mid\"');",
"assert(myTest(7) === \"High\", 'message: myTest(7) should return \"High\"');",
"assert(myTest(8) === \"High\", 'message: myTest(8) should return \"High\"');",
"assert(myTest(9) === \"High\", 'message: myTest(9) should return \"High\"');",
"assert(!/else/g.test(code) || !/if/g.test(code), 'message: You should not use any if or else statements');",
"assert(code.match(/case/g).length === 9, 'message: You should have nine case statements');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244e0",
"title": "Replacing If Else Chains with Switch",
"description": [
"If you have many options to choose from, a switch statement can be easier to write than many chained if/if else statements. The following:",
"
switch (val) { case 1: answer = \"a\"; break; case 2: answer = \"b\"; break; default: answer = \"c\"; }
",
"
Instructions
",
"Change the chained if/if else statements into a switch statement."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function myTest(val) {",
" var answer = \"\";",
" // Only change code below this line",
" ",
" if (val === \"bob\") {",
" answer = \"Marley\";",
" } else if (val === 42) {",
" answer = \"The Answer\";",
" } else if (val === 1) {",
" answer = \"There is no #1\";",
" } else if (val === 99) {",
" answer = \"Missed me by this much!\";",
" } else if (val === 7) {",
" answer = \"Ate Nine\";",
" }",
" ",
" // Only change code above this line ",
" return answer; ",
"}",
"",
"// Change this value to test",
"myTest(7);",
""
],
"solutions": [
"function myTest(val) {\n var answer = \"\";\n\n switch (val) {\n case \"bob\":\n answer = \"Marley\";\n break;\n case 42:\n answer = \"The Answer\";\n break;\n case 1:\n answer = \"There is no #1\";\n break;\n case 99:\n answer = \"Missed me by this much!\";\n break;\n case 7:\n answer = \"Ate Nine\";\n }\n return answer; \n}"
],
"tests": [
"assert(!/else/g.test(code), 'message: You should not use any else statements');",
"assert(!/if/g.test(code), 'message: You should not use any if statements');",
"assert(code.match(/break/g).length >= 4, 'message: You should have at least four break statements');",
"assert(myTest(\"bob\") === \"Marley\", 'message: myTest(\"bob\") should be \"Marley\"');",
"assert(myTest(42) === \"The Answer\", 'message: myTest(42) should be \"The Answer\"');",
"assert(myTest(1) === \"There is no #1\", 'message: myTest(1) should be \"There is no #1\"');",
"assert(myTest(99) === \"Missed me by this much!\", 'message: myTest(99) should be \"Missed me by this much!\"');",
"assert(myTest(7) === \"Ate Nine\", 'message: myTest(7) should be \"Ate Nine\"');",
"assert(myTest(\"John\") === \"\", 'message: myTest(\"John\") should be \"\" (empty string)');",
"assert(myTest(156) === \"\", 'message: myTest(156) should be \"\" (empty string)');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "5679ceb97cbaa8c51670a16b",
"title": "Returning Boolean Values from Functions",
"description": [
"You may recall from Comparison with the Equality Operator that all comparison operators return a boolean true or false value.",
"A common anti-pattern is to use an if/else statement to do a comparison and then returntrue/false:",
"
function isEqual(a,b) { if (a === b) { return true; } else { return false; } }
",
"Since === returns true or false, we can simply return the result of the comparison:",
"
function isEqual(a,b) { return a === b; }
",
"
Instructions
",
"Fix the function isLess to remove the if/else statements."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function isLess(a, b) {",
" // Fix this code",
" if (a < b) {",
" return true;",
" } else {",
" return false;",
" }",
"}",
"",
"// Change these values to test",
"isLess(10, 15);"
],
"tail": [
""
],
"solutions": [
"function isLess(a, b) {\n return a < b;\n}"
],
"tests": [
"assert(isLess(10,15) === true, 'message: isLess(10,15) should return true');",
"assert(isLess(15, 10) === false, 'message: isLess(15,10) should return false');",
"assert(!/if|else/g.test(code), 'message: You should not use any if or else statements');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244c4",
"title": "Return Early Pattern for Functions",
"description": [
"When a return statement is reached, the execution of the current function stops and control returns to the calling location.",
"Example",
"
function myFun() { console.log(\"Hello\"); return \"World\"; console.log(\"byebye\") } myFun();
",
"The above outputs \"Hello\" to the console, returns \"World\", but \"byebye\" is never output, because the function exits at the return statement.",
"
Instructions
",
"Modify the function abTest so that if a or b are less than 0 the function will immediately exit with a value of undefined.",
"Hint Remember that undefined is a keyword, not a string."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"function abTest(a, b) {",
" // Only change code below this line",
" ",
" ",
" ",
" // Only change code above this line",
"",
" return Math.round(Math.pow(Math.sqrt(a) + Math.sqrt(b), 2));",
"}",
"",
"// Change values below to test your code",
"abTest(2,2);"
],
"tail": [
""
],
"solutions": [
"function abTest(a, b) {\n if(a < 0 || b < 0) {\n return undefined;\n } \n return Math.round(Math.pow(Math.sqrt(a) + Math.sqrt(b), 2));\n}"
],
"tests": [
"assert(typeof abTest(2,2) === 'number' , 'message: abTest(2,2) should return a number');",
"assert(abTest(2,2) === 8 , 'message: abTest(2,2) should return 8');",
"assert(abTest(-2,2) === undefined , 'message: abTest(-2,2) should return undefined');",
"assert(abTest(2,-2) === undefined , 'message: abTest(2,-2) should return undefined');",
"assert(abTest(2,8) === 18 , 'message: abTest(2,8) should return 18');",
"assert(abTest(3,3) === 12 , 'message: abTest(3,3) should return 12');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "565bbe00e9cc8ac0725390f4",
"title": "Counting Cards",
"description": [
"In the casino game Blackjack, a player can gain an advantage over the house by keeping track of the relative number of high and low cards remaining in the deck. This is called Card Counting.",
"Having more high cards remaining in the deck favors the player. Each card is assigned a value according to the table below. When the count is positive, the player should bet high. When the count is zero or negative, the player should bet low.",
"
Value
Cards
+1
2, 3, 4, 5, 6
0
7, 8, 9
-1
10, 'J', 'Q', 'K','A'
",
"You will write a card counting function. It will receive a card parameter and increment or decrement the global count variable according to the card's value (see table). The function will then return a string with the current count and the string \"Bet\" if the count is positive, or \"Hold\" if the count is zero or negative. The current count and the player's decision (\"Bet\" or \"Hold\") should be separated by a single space.
",
"Example Output \"-3 Hold\" \"5 Bet\""
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var count = 0;",
"",
"function cc(card) {",
" // Only change code below this line",
" ",
" ",
" return \"Change Me\";",
" // Only change code above this line",
"}",
"",
"// Add/remove calls to test your function.",
"// Note: Only the last will display",
"cc(2); cc(3); cc(7); cc('K'); cc('A');"
],
"solutions": [
"var count = 0;\nfunction cc(card) {\n switch(card) {\n case 2:\n case 3:\n case 4:\n case 5:\n case 6:\n count++;\n break;\n case 10:\n case 'J':\n case 'Q':\n case 'K':\n case 'A':\n count--;\n }\n if(count > 0) {\n return count + \" Bet\";\n } else {\n return count + \" Hold\";\n }\n}"
],
"tests": [
"assert((function(){ count = 0; cc(2);cc(3);cc(4);cc(5);var out = cc(6); if(out === \"5 Bet\") {return true;} return false; })(), 'message: Cards Sequence 2, 3, 4, 5, 6 should return \"5 Bet\"');",
"assert((function(){ count = 0; cc(7);cc(8);var out = cc(9); if(out === \"0 Hold\") {return true;} return false; })(), 'message: Cards Sequence 7, 8, 9 should return \"0 Hold\"');",
"assert((function(){ count = 0; cc(10);cc('J');cc('Q');cc('K');var out = cc('A'); if(out === \"-5 Hold\") {return true;} return false; })(), 'message: Cards Sequence 10, J, Q, K, A should return \"-5 Hold\"');",
"assert((function(){ count = 0; cc(3);cc(2);cc('A');cc(10);var out = cc('K'); if(out === \"-1 Hold\") {return true;} return false; })(), 'message: Cards Sequence 3, 2, A, 10, K should return \"-1 Hold\"');"
],
"type": "checkpoint",
"challengeType": 1
},
{
"id": "bg9998c9c99feddfaeb9bdef",
"title": "Build JavaScript Objects",
"description": [
"You may have heard the term object before.",
"Objects are similar to arrays, except that instead of using indexes to access and modify their data, you access the data in objects through what are called properties.",
"Here's a sample object:",
"
",
"Objects are useful for storing data in a structured way, and can represent real world objects, like a cat.",
"
Instructions
",
"Make an object that represents a dog called myDog which contains the properties \"name\" (a string), \"legs\", \"tails\" and \"friends\".",
"You can set these object properties to whatever values you want, as long \"name\" is a string, \"legs\" and \"tails\" are numbers, and \"friends\" is an array."
],
"challengeSeed": [
"// Example",
"var ourDog = {",
" \"name\": \"Camper\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"friends\": [\"everything!\"]",
"};",
"",
"// Only change code below this line.",
"",
"var myDog = {",
" ",
" ",
" ",
" ",
"};"
],
"tail": [
"(function(z){return z;})(myDog);"
],
"solutions": [
"var myDog = {\n \"name\": \"Camper\",\n \"legs\": 4,\n \"tails\": 1,\n \"friends\": [\"everything!\"] \n};"
],
"tests": [
"assert((function(z){if(z.hasOwnProperty(\"name\") && z.name !== undefined && typeof z.name === \"string\"){return true;}else{return false;}})(myDog), 'message: myDog should contain the property name and it should be a string.');",
"assert((function(z){if(z.hasOwnProperty(\"legs\") && z.legs !== undefined && typeof z.legs === \"number\"){return true;}else{return false;}})(myDog), 'message: myDog should contain the property legs and it should be a number.');",
"assert((function(z){if(z.hasOwnProperty(\"tails\") && z.tails !== undefined && typeof z.tails === \"number\"){return true;}else{return false;}})(myDog), 'message: myDog should contain the property tails and it should be a number.');",
"assert((function(z){if(z.hasOwnProperty(\"friends\") && z.friends !== undefined && Array.isArray(z.friends)){return true;}else{return false;}})(myDog), 'message: myDog should contain the property friends and it should be an array.');",
"assert((function(z){return Object.keys(z).length === 4;})(myDog), 'message: myDog should only contain all the given properties.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Construye objetos en JavaScript",
"descriptionEs": [
"Es posible que haya oído el término objeto antes.",
"Los objetos son similares a los vectores, excepto que en lugar de utilizar los índices para acceder y modificar sus datos, pueden accederse mediante lo que se llama propiedades.",
"Esto es un objeto de ejemplo:",
"var cat = {",
" \"name\": \"Whiskers\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"enemies\": [\"Water\", \"Dogs\"]",
"};",
"Los objetos son útiles para almacenar datos de manera estructurada, y pueden representar objetos del mundo real, como un gato.",
"Vamos a tratar de hacer un objeto que representa un perro, lo llamaremos mydog y contendrá las propiedades \"name\" (una cadena con el nombre), \"legs\" (piernas), \"tails\" (colas) y \"friends\" (amigos). ",
"Podrás establecer estas propiedades del objeto en los valores que desees, siempre y cuando \"name\" sea una cadena, \"legs\" y \"tails\" sean números, y \"friends\" sea un vector."
]
},
{
"id": "56533eb9ac21ba0edf2244c7",
"title": "Accessing Objects Properties with the Dot Operator",
"description": [
"There are two ways to access the properties of an object: the dot operator (.) and bracket notation ([]), similar to an array.",
"The dot operator is what you use when you know the name of the property you're trying to access ahead of time.",
"Here is a sample of using the dot operator (.) to read an object property:",
"
var myObj = { prop1: \"val1\", prop2: \"val2\" }; var prop1val = myObj.prop1; // val1 var prop2val = myObj.prop2; // val2
",
"
Instructions
",
"Read in the property values of testObj using dot notation. Set the property hat to the variable hatValue and the property shirt to shirtValue."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var testObj = {",
" \"hat\": \"ballcap\",",
" \"shirt\": \"jersey\",",
" \"shoes\": \"cleats\"",
"};",
"",
"// Only change code below this line",
"",
"var hatValue = testObj; // Change this line",
"var shirtValue = testObj; // Change this line"
],
"tail": [
"(function(a,b) { return \"hatValue = '\" + a + \"', shirtValue = '\" + b + \"'\"; })(hatValue,shirtValue);"
],
"solutions": [
"var testObj = {\n \"hat\": \"ballcap\",\n \"shirt\": \"jersey\",\n \"shoes\": \"cleats\"\n};\n\nvar hatValue = testObj.hat; \nvar shirtValue = testObj.shirt;"
],
"tests": [
"assert(typeof hatValue === 'string' , 'message: hatValue should be a string');",
"assert(hatValue === 'ballcap' , 'message: The value of hatValue should be \"ballcap\"');",
"assert(typeof shirtValue === 'string' , 'message: shirtValue should be a string');",
"assert(shirtValue === 'jersey' , 'message: The value of shirtValue should be \"jersey\"');",
"assert(code.match(/testObj\\.\\w+/g).length > 1, 'message: You should use dot notation twice');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244c8",
"title": "Accessing Objects Properties with Bracket Notation",
"description": [
"The second way to access the properties of an object is bracket notation ([]). If the property of the object you are trying to access has a space in it, you will need to use bracket notation.",
"Here is a sample of using bracket notation to read an object property:",
"
",
"Note that property names with spaces in them must be in quotes (single or double).",
"
Instructions
",
"Read the values of the properties \"an entree\" and \"the drink\" of testObj using bracket notation."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var testObj = {",
" \"an entree\": \"hamburger\",",
" \"my side\": \"veggies\",",
" \"the drink\": \"water\"",
"};",
"",
"// Only change code below this line",
"",
"var entreeValue = testObj; // Change this line",
"var drinkValue = testObj; // Change this line"
],
"tail": [
"(function(a,b) { return \"entreeValue = '\" + a + \"', drinkValue = '\" + b + \"'\"; })(entreeValue,drinkValue);"
],
"solutions": [
"var testObj = {\n \"an entree\": \"hamburger\",\n \"my side\": \"veggies\",\n \"the drink\": \"water\"\n};\nvar entreeValue = testObj[\"an entree\"];\nvar drinkValue = testObj['the drink'];"
],
"tests": [
"assert(typeof entreeValue === 'string' , 'message: entreeValue should be a string');",
"assert(entreeValue === 'hamburger' , 'message: The value of entreeValue should be \"hamburger\"');",
"assert(typeof drinkValue === 'string' , 'message: drinkValue should be a string');",
"assert(drinkValue === 'water' , 'message: The value of drinkValue should be \"water\"');",
"assert(code.match(/testObj\\s*?\\[('|\")[^'\"]+\\1\\]/g).length > 1, 'message: You should use bracket notation twice');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244c9",
"title": "Accessing Objects Properties with Variables",
"description": [
"Another use of bracket notation on objects is to use a variable to access a property. This can be very useful for iterating through lists of the object properties or for doing the lookup.",
"Here is an example of using a variable to access a property:",
"
var someProp = \"propName\"; var myObj = { propName: \"Some Value\" } myObj[someProp]; // \"Some Value\"
",
"Here is one more:",
"
var myDog = \"Hunter\"; var dogs = { Fido: \"Mutt\",\n Hunter: \"Doberman\",\n Snoopie: \"Beagle\" } var breed = dogs[myDog]; // \"Hunter\" console.log(breed)// \"Doberman\"
",
"Note that we do not use quotes around the variable name when using it to access the property because we are using the value of the variable, not the name",
"
Instructions
",
"Use the playerNumber variable to lookup player 16 in testObj using bracket notation."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var testObj = {",
" 12: \"Namath\",",
" 16: \"Montana\",",
" 19: \"Unitas\"",
"};",
"",
"// Only change code below this line;",
"",
"var playerNumber; // Change this Line",
"var player = testObj; // Change this Line"
],
"tail": [
"if(typeof player !== \"undefined\"){(function(v){return v;})(player);}"
],
"solutions": [
"var testObj = {\n 12: \"Namath\",\n 16: \"Montana\",\n 19: \"Unitas\"\n};\nvar playerNumber = 16;\nvar player = testObj[playerNumber];"
],
"tests": [
"assert(typeof playerNumber === 'number', 'message: playerNumber should be a number');",
"assert(typeof player === 'string', 'message: The variable player should be a string');",
"assert(player === 'Montana', 'message: The value of player should be \"Montana\"');",
"assert(/testObj\\s*?\\[\\s*playerNumber\\s*\\]/.test(code),'message: You should use bracket notation to access testObj');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "bg9999c9c99feddfaeb9bdef",
"title": "Updating Object Properties",
"description": [
"After you've created a JavaScript object, you can update its properties at any time just like you would update any other variable. You can use either dot or bracket notation to update.",
"For example, let's look at ourDog:",
"
",
"Since he's a particularly happy dog, let's change his name to \"Happy Camper\". Here's how we update his object's name property:",
"ourDog.name = \"Happy Camper\"; or",
"ourDog[\"name\"] = \"Happy Camper\";",
"Now when we evaluate ourDog.name, instead of getting \"Camper\", we'll get his new name, \"Happy Camper\".",
"
Instructions
",
"Update the myDog object's name property. Let's change her name from \"Coder\" to \"Happy Coder\". You can use either dot or bracket notation."
],
"challengeSeed": [
"// Example",
"var ourDog = {",
" \"name\": \"Camper\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"friends\": [\"everything!\"]",
"};",
"",
"ourDog.name = \"Happy Camper\";",
"",
"// Setup",
"var myDog = {",
" \"name\": \"Coder\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"friends\": [\"Free Code Camp Campers\"]",
"};",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"(function(z){return z;})(myDog);"
],
"solutions": [
"var myDog = {\n \"name\": \"Coder\",\n \"legs\": 4,\n \"tails\": 1,\n \"friends\": [\"Free Code Camp Campers\"]\n};\nmyDog.name = \"Happy Coder\";"
],
"tests": [
"assert(/happy coder/gi.test(myDog.name), 'message: Update myDog's \"name\" property to equal \"Happy Coder\".');",
"assert(/\"name\": \"Coder\"/.test(code), 'message: Do not edit the myDog definition');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Actualiza las propiedades de un objeto en JavaScript",
"descriptionEs": [
"Después de que hayas creado un objeto de JavaScript, puedes actualizar sus propiedades en cualquier momento, tal y como harías con cualquier otra variable.",
"Por ejemplo, echemos un vistazo a ourDog:",
"var ourDog = {",
" \"name\": \"Camper\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"friends\": [\"everything!\"]",
"};",
"Dado que es un perro particularmente feliz, vamos a cambiar su nombre a \"Happy Camper\". Así es como actualizamos la propiedad nombre del objeto: ",
"ourDog.name = \"Happy Camper\";",
"Ahora, cuando ejecutemos return ourDog.name, en lugar de obtener \"Camper\", vamos a recibir su nuevo nombre, \"Happy Camper\".",
"Vamos a actualizar la propiedad del objeto mydog. Cambiemos su nombre de \"Coder\" a \"Happy Coder\"."
]
},
{
"id": "bg9999c9c99feedfaeb9bdef",
"title": "Add New Properties to a JavaScript Object",
"description": [
"You can add new properties to existing JavaScript objects the same way you would modify them.",
"Here's how we would add a \"bark\" property to ourDog:",
"ourDog.bark = \"bow-wow\"; ",
"or",
"ourDog[\"bark\"] = \"bow-wow\";",
"Now when we evaluate ourDog.bark, we'll get his bark, \"bow-wow\".",
"
Instructions
",
"Add a \"bark\" property to myDog and set it to a dog sound, such as \"woof\". You may use either dot or bracket notation."
],
"challengeSeed": [
"// Example",
"var ourDog = {",
" \"name\": \"Camper\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"friends\": [\"everything!\"]",
"};",
"",
"ourDog.bark = \"bow-wow\";",
"",
"// Setup",
"var myDog = {",
" \"name\": \"Happy Coder\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"friends\": [\"Free Code Camp Campers\"]",
"};",
"",
"// Only change code below this line.",
""
],
"tail": [
"(function(z){return z;})(myDog);"
],
"solutions": [
"var myDog = {\n \"name\": \"Happy Coder\",\n \"legs\": 4,\n \"tails\": 1,\n \"friends\": [\"Free Code Camp Campers\"]\n};\nmyDog.bark = \"Woof Woof\";"
],
"tests": [
"assert(myDog.bark !== undefined, 'message: Add the property \"bark\" to myDog.');",
"assert(!/bark[^\\n]:/.test(code), 'message: Do not add \"bark\" to the setup section');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Añade nuevas propiedades a un objeto JavaScript",
"descriptionEs": [
"Puedes añadir nuevas propiedades a objetos existente de la misma forma que usarías para modificarlos.",
"Así es como añadimos una propiedad \"bark\" (ladra) a nuestro objeto ourDog:",
"ourDog.bark = \"bow-wow\";",
"Ahora, cuando ejecutemos return ourDog.bark, vamos a recbir su ladrido, \" bow-wow \".",
"Vamos a añadir una propiedad ladra a myDog y a ponerle un sonido de perro, tal como \"woof\"."
]
},
{
"id": "bg9999c9c99fdddfaeb9bdef",
"title": "Delete Properties from a JavaScript Object",
"description": [
"We can also delete properties from objects like this:",
"delete ourDog.bark;",
"
Instructions
",
"Delete the \"tails\" property from myDog. You may use either dot or bracket notation."
],
"challengeSeed": [
"// Example",
"var ourDog = {",
" \"name\": \"Camper\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"friends\": [\"everything!\"],",
" \"bark\": \"bow-wow\"",
"};",
"",
"delete ourDog.bark;",
"",
"// Setup",
"var myDog = {",
" \"name\": \"Happy Coder\",",
" \"legs\": 4,",
" \"tails\": 1,",
" \"friends\": [\"Free Code Camp Campers\"],",
" \"bark\": \"woof\"",
"};",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"(function(z){return z;})(myDog);"
],
"solutions": [
"var ourDog = {\n \"name\": \"Camper\",\n \"legs\": 4,\n \"tails\": 1,\n \"friends\": [\"everything!\"],\n \"bark\": \"bow-wow\"\n};\n\nvar myDog = {\n \"name\": \"Happy Coder\",\n \"legs\": 4,\n \"tails\": 1,\n \"friends\": [\"Free Code Camp Campers\"],\n \"bark\": \"woof\"\n};\n\ndelete myDog.tails;"
],
"tests": [
"assert(myDog.tails === undefined, 'message: Delete the property \"tails\" from myDog.');",
"assert(code.match(/\"tails\": 1/g).length > 1, 'message: Do not modify the myDog setup');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Elimina propiedades de un objeto JavaScript",
"descriptionEs": [
"También podemos eliminar propiedades de los objetos de esta manera:",
"delete ourDog.bark;",
"Borremos la propiedad \"tails\" de myDog."
]
},
{
"id": "56533eb9ac21ba0edf2244ca",
"title": "Using Objects for Lookups",
"description": [
"Objects can be thought of as a key/value storage, like a dictionary. If you have tabular data, you can use an object to \"lookup\" values rather than a switch statement or an if/else chain. This is most useful when you know that your input data is limited to a certain range.",
"Here is an example of a simple reverse alphabet lookup:",
"
",
"Convert the switch statement into a lookup table called lookup. Use it to lookup val and assign the associated string to the result variable."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"function phoneticLookup(val) {",
" var result = \"\";",
"",
" // Only change code below this line",
" switch(val) {",
" case \"alpha\": ",
" result = \"Adams\";",
" break;",
" case \"bravo\": ",
" result = \"Boston\";",
" break;",
" case \"charlie\": ",
" result = \"Chicago\";",
" break;",
" case \"delta\": ",
" result = \"Denver\";",
" break;",
" case \"echo\": ",
" result = \"Easy\";",
" break;",
" case \"foxtrot\": ",
" result = \"Frank\";",
" }",
"",
" // Only change code above this line",
" return result;",
"}",
"",
"// Change this value to test",
"phoneticLookup(\"charlie\");"
],
"solutions": [
"function phoneticLookup(val) {\n var result = \"\";\n\n var lookup = {\n alpha: \"Adams\",\n bravo: \"Boston\",\n charlie: \"Chicago\",\n delta: \"Denver\",\n echo: \"Easy\",\n foxtrot: \"Frank\"\n };\n\n result = lookup[val];\n\n return result;\n}"
],
"tests": [
"assert(phoneticLookup(\"alpha\") === 'Adams', 'message: phoneticLookup(\"alpha\") should equal \"Adams\"');",
"assert(phoneticLookup(\"bravo\") === 'Boston', 'message: phoneticLookup(\"bravo\") should equal \"Boston\"');",
"assert(phoneticLookup(\"charlie\") === 'Chicago', 'message: phoneticLookup(\"charlie\") should equal \"Chicago\"');",
"assert(phoneticLookup(\"delta\") === 'Denver', 'message: phoneticLookup(\"delta\") should equal \"Denver\"');",
"assert(phoneticLookup(\"echo\") === 'Easy', 'message: phoneticLookup(\"echo\") should equal \"Easy\"');",
"assert(phoneticLookup(\"foxtrot\") === 'Frank', 'message: phoneticLookup(\"foxtrot\") should equal \"Frank\"');",
"assert(typeof phoneticLookup(\"\") === 'undefined', 'message: phoneticLookup(\"\") should equal undefined');",
"assert(!/case|switch|if/g.test(code), 'message: You should not use case, switch, or if statements'); "
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "567af2437cbaa8c51670a16c",
"title": "Testing Objects for Properties",
"description": [
"Sometimes it is useful to check if the property of a given object exists or not. We can use the .hasOwnProperty(propname) method of objects to determine if that object has the given property name. .hasOwnProperty() returns true or false if the property is found or not.",
"Example",
"
",
"This is an array of objects and the object has various pieces of metadata about an album. It also has a nested formats array. Additional album records could be added to the top level array.",
"Note You will need a comma in between objects in JSON objects with more than one object in the array.",
"
Instructions
",
"Add a new album to the myMusic JSON object. Add artist and title strings, release_year number, and a formats array of strings."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"var myMusic = [",
" {",
" \"artist\": \"Billy Joel\",",
" \"title\": \"Piano Man\",",
" \"release_year\": 1973,",
" \"formats\": [ ",
" \"CS\", ",
" \"8T\", ",
" \"LP\" ],",
" \"gold\": true",
" }",
" // Add record here",
"];",
""
],
"tail": [
"(function(x){ if (Array.isArray(x)) { return JSON.stringify(x); } return \"myMusic is not an array\"})(myMusic);"
],
"solutions": [
"var myMusic = [\n {\n \"artist\": \"Billy Joel\",\n \"title\": \"Piano Man\",\n \"release_year\": 1973,\n \"formats\": [ \n \"CS\", \n \"8T\", \n \"LP\" ],\n \"gold\": true\n }, \n {\n \"artist\": \"ABBA\",\n \"title\": \"Ring Ring\",\n \"release_year\": 1973,\n \"formats\": [ \n \"CS\", \n \"8T\", \n \"LP\",\n \"CD\",\n ]\n }\n];"
],
"tests": [
"assert(Array.isArray(myMusic), 'message: myMusic should be an array');",
"assert(myMusic.length > 1, 'message: myMusic should have at least two elements');",
"assert(typeof myMusic[1] === 'object', 'message: myMusic[1] should be an object');",
"assert(Object.keys(myMusic[1]).length > 3, 'message: myMusic[1] should have at least 4 properties');",
"assert(myMusic[1].hasOwnProperty('artist') && typeof myMusic[1].artist === 'string', 'message: myMusic[1] should contain an artist property which is a string');",
"assert(myMusic[1].hasOwnProperty('title') && typeof myMusic[1].title === 'string', 'message: myMusic[1] should contain a title property which is a string');",
"assert(myMusic[1].hasOwnProperty('release_year') && typeof myMusic[1].release_year === 'number', 'message: myMusic[1] should contain a release_year property which is a number');",
"assert(myMusic[1].hasOwnProperty('formats') && Array.isArray(myMusic[1].formats), 'message: myMusic[1] should contain a formats property which is an array');",
"assert(myMusic[1].formats.every(function(item) { return (typeof item === \"string\")}) && myMusic[1].formats.length > 1, 'message: formats should be an array of strings with at least two elements');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244cc",
"title": "Accessing Nested Objects in JSON",
"description": [
"The properties and sub-properties of JSON objects can be accessed by chaining together the dot or bracket notation.",
"Here is a nested JSON Object:",
"
",
"Retrieve the second tree from the variable myPlants using object dot and array bracket notation."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var myPlants = [",
" { ",
" type: \"flowers\",",
" list: [",
" \"rose\",",
" \"tulip\",",
" \"dandelion\"",
" ]",
" },",
" {",
" type: \"trees\",",
" list: [",
" \"fir\",",
" \"pine\",",
" \"birch\"",
" ]",
" } ",
"];",
"",
"// Only change code below this line",
"",
"var secondTree = \"\"; // Change this line",
""
],
"tail": [
"(function(x) { ",
" if(typeof x != 'undefined') { ",
" return \"secondTree = \" + x;",
" }",
" return \"secondTree is undefined\";",
"})(secondTree);"
],
"solutions": [
"var myPlants = [\n { \n type: \"flowers\",\n list: [\n \"rose\",\n \"tulip\",\n \"dandelion\"\n ]\n },\n {\n type: \"trees\",\n list: [\n \"fir\",\n \"pine\",\n \"birch\"\n ]\n } \n];\n\n// Only change code below this line\n\nvar secondTree = myPlants[1].list[1];"
],
"tests": [
"assert(secondTree === \"pine\", 'message: secondTree should equal \"pine\"');",
"assert(/=\\s*myPlants\\[1\\].list\\[1\\]/.test(code), 'message: Use dot and bracket notation to access myPlants');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244cf",
"title": "Record Collection",
"description": [
"You are given a JSON object representing (a small part of) your record collection. Each album is identified by a unique id number and has several properties. Not all albums have complete information.",
"Write a function which takes an id, a property (prop), and a value.",
"For the given id in collection:",
"If value is non-blank (value !== \"\") and prop is not \"tracks\" then update or set the value for the prop.",
"If the prop is \"tracks\" and value is non-blank, push the value onto the end of the tracks array.",
"If value is blank, delete that prop.",
"Always return the entire collection object.",
"Note Don't forget to use bracket notation when accessing object properties with variables."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Setup",
"var collection = {",
" 2548: {",
" album: \"Slippery When Wet\",",
" artist: \"Bon Jovi\",",
" tracks: [ ",
" \"Let It Rock\", ",
" \"You Give Love a Bad Name\" ",
" ]",
" },",
" 2468: {",
" album: \"1999\",",
" artist: \"Prince\",",
" tracks: [ ",
" \"1999\", ",
" \"Little Red Corvette\" ",
" ]",
" },",
" 1245: {",
" artist: \"Robert Palmer\",",
" tracks: [ ]",
" },",
" 5439: {",
" album: \"ABBA Gold\"",
" }",
"};",
"// Keep a copy of the collection for tests",
"var collectionCopy = JSON.parse(JSON.stringify(collection));",
"",
"// Only change code below this line",
"function update(id, prop, value) {",
"",
"",
" return collection;",
"}",
"",
"// Alter values below to test your code",
"update(5439, \"artist\", \"ABBA\");",
""
],
"tail": [
"(function(x) { return \"collection = \\n\" + JSON.stringify(x, '\\n', 2); })(collection);"
],
"solutions": [
"var collection = {\n 2548: {\n album: \"Slippery When Wet\",\n artist: \"Bon Jovi\",\n tracks: [ \n \"Let It Rock\", \n \"You Give Love a Bad Name\" \n ]\n },\n 2468: {\n album: \"1999\",\n artist: \"Prince\",\n tracks: [ \n \"1999\", \n \"Little Red Corvette\" \n ]\n },\n 1245: {\n artist: \"Robert Palmer\",\n tracks: [ ]\n },\n 5439: {\n album: \"ABBA Gold\"\n }\n};\n// Keep a copy of the collection for tests\nvar collectionCopy = JSON.parse(JSON.stringify(collection));\n\n// Only change code below this line\nfunction update(id, prop, value) {\n if(value !== \"\") {\n if(prop === \"tracks\") {\n collection[id][prop].push(value);\n } else {\n collection[id][prop] = value;\n }\n } else {\n delete collection[id][prop];\n }\n\n return collection;\n}"
],
"tests": [
"collection = collectionCopy; assert(update(5439, \"artist\", \"ABBA\")[5439][\"artist\"] === \"ABBA\", 'message: After update(5439, \"artist\", \"ABBA\"), artist should be \"ABBA\"');",
"update(2548, \"artist\", \"\"); assert(!collection[2548].hasOwnProperty(\"artist\"), 'message: After update(2548, \"artist\", \"\"), artist should not be set');",
"assert(update(1245, \"tracks\", \"Addicted to Love\")[1245][\"tracks\"].length === 1, 'message: After update(1245, \"tracks\", \"Addicted to Love\"), tracks should have a length of 1');",
"update(2548, \"tracks\", \"\"); assert(!collection[2548].hasOwnProperty(\"tracks\"), 'message: After update(2548, \"tracks\", \"\"), tracks should not be set');"
],
"type": "checkpoint",
"challengeType": 1
},
{
"id": "cf1111c1c11feddfaeb5bdef",
"title": "Iterate with JavaScript For Loops",
"description": [
"You can run the same code multiple times by using a loop.",
"The most common type of JavaScript loop is called a \"for loop\" because it runs \"for\" a specific number of times.",
"For loops are declared with three optional expressions separated by semicolons:",
"for ([initialization]; [condition]; [final-expression])",
"The initialization statement is executed one time only before the loop starts. It is typically used to define and setup your loop variable.",
"The condition statement is evaluated at the beginning of every loop iteration and will continue as long as it evalutes to true. When condition is false at the start of the iteration, the loop will stop executing. This means if condition starts as false, your loop will never execute.",
"The final-expression is executed at the end of each loop iteration, prior to the next condition check and is usually used to increment or decrement your loop counter.",
"In the following example we initialize with i = 0 and iterate while our condition i < 5 is true. We'll increment i by 1 in each loop iteration with i++ as our final-expression.",
"
var ourArray = []; for (var i = 0; i < 5; i++) { ourArray.push(i); }
",
"ourArray will now contain [0,1,2,3,4].",
"
Instructions
",
"Use a for loop to work to push the values 1 through 5 onto myArray."
],
"challengeSeed": [
"// Example",
"var ourArray = [];",
"",
"for (var i = 0; i < 5; i++) {",
" ourArray.push(i);",
"}",
"",
"// Setup",
"var myArray = [];",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"if (typeof myArray !== \"undefined\"){(function(){return myArray;})();}"
],
"solutions": [
"var ourArray = [];\nfor (var i = 0; i < 5; i++) {\n ourArray.push(i);\n}\nvar myArray = [];\nfor (var i = 1; i < 6; i++) {\n myArray.push(i);\n}"
],
"tests": [
"assert(code.match(/for\\s*\\(/g).length > 1, 'message: You should be using a for loop for this.');",
"assert.deepEqual(myArray, [1,2,3,4,5], 'message: myArray should equal [1,2,3,4,5].');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Iterar con JavaScript en ciclos",
"descriptionEs": [
"Puede ejecutar el mismo código varias veces mediante el uso de un ciclo.",
"El tipo más común de bucle de JavaScript se llama \"ciclo for\"porque se ejecuta \"por\" (for) un número específico de veces.",
"Los ciclos for se declaran con tres expresiones opcionales separadas por punto y coma:",
"for ([inicialización]; [condición]; [expresión-final])",
"La inicialización se ejecuta sólo una vez antes de que empiece el ciclo. Normalmente se utiliza para definir e inicializar su variable de ciclo. ",
"La expresión condición se evalúa al principio de cada iteración del ciclo y continuará en el ciclo siempre y cuando sea verdadera (true). Cuando la condición sea falsa (false) al comienzo de la iteración, se detendrá la ejecución del ciclo. Esto significa que si la condición inicia en el valor falso false, el ciclo no se ejecutará. ",
"La expresión final se ejecuta al final de cada repetición del ciclo, antes del siguiente chequeo de la condición y se utiliza generalmente para aumentar o disminuir el contador del ciclo.",
"En el siguiente ejemplo inicializamos con i = 0 e iteramos mientras nuestra condición i <5 sea verdadera. Vamos a incrementar i en 1 en cada iteración del ciclo con i++ como nuestra expresión final. ",
"var ourArray = [];",
"for (var i = 0; i < 5; i++) {",
" ourArray.push(i);",
"}",
"ourArray ahora contendrá [0,1,2,3,4].",
"Vamos a utilizar un ciclo for para empujar los valores del 1 al 5 en myArray."
]
},
{
"id": "56104e9e514f539506016a5c",
"title": "Iterate Odd Numbers With a For Loop",
"description": [
"For loops don't have to iterate one at a time. By changing our final-expression, we can count by even numbers.",
"We'll start at i = 0 and loop while i < 10. We'll increment i by 2 each loop with i += 2.",
"
var ourArray = []; for (var i = 0; i < 10; i += 2) { ourArray.push(i); }
",
"ourArray will now contain [0,2,4,6,8].",
"Let's change our initialization so we can count by odd numbers.",
"
Instructions
",
"Push the odd numbers from 1 through 9 to myArray using a for loop."
],
"challengeSeed": [
"// Example",
"var ourArray = [];",
"",
"for (var i = 0; i < 10; i += 2) {",
" ourArray.push(i);",
"}",
"",
"// Setup",
"var myArray = [];",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"if(typeof myArray !== \"undefined\"){(function(){return myArray;})();}"
],
"solutions": [
"var ourArray = [];\nfor (var i = 0; i < 10; i += 2) {\n ourArray.push(i);\n}\nvar myArray = [];\nfor (var i = 1; i < 10; i += 2) {\n myArray.push(i);\n}"
],
"tests": [
"assert(code.match(/for\\s*\\(/g).length > 1, 'message: You should be using a for loop for this.');",
"assert.deepEqual(myArray, [1,3,5,7,9], 'message: myArray should equal [1,3,5,7,9].');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Itera por los números pares con un ciclo for",
"descriptionEs": [
"Los ciclos for no siempre iteran incrementado de a uno. Cambiando nuestra expresión final, podemos contar los números pares.",
"Vamos a empezar con i = 0 e iterar mientras i <10. Vamos a incrementar i de a 2 en cada iteración i + = 2. ",
"var ourArray = [];",
"for (var i = 0; i < 10; i += 2) {",
" ourArray.push(i);",
"}",
"ourArray ahora contendrá [0,2,4,6,8].",
"Vamos a cambiar nuestra inicialización y expresión final para que podamos contar los números impares.",
"Empuja los números impares del 1 al 9 en myArray utilizando un ciclo for."
]
},
{
"id": "56105e7b514f539506016a5e",
"title": "Count Backwards With a For Loop",
"description": [
"A for loop can also count backwards, so long as we can define the right conditions.",
"In order to count backwards by twos, we'll need to change our initialization, condition, and final-expression.",
"We'll start at i = 10 and loop while i > 0. We'll decrement i by 2 each loop with i -= 2.",
"
var ourArray = []; for (var i=10; i > 0; i-=2) { ourArray.push(i); }
",
"ourArray will now contain [10,8,6,4,2].",
"Let's change our initialization and final-expression so we can count backward by twos by odd numbers.",
"
Instructions
",
"Push the odd numbers from 9 through 1 to myArray using a for loop."
],
"challengeSeed": [
"// Example",
"var ourArray = [];",
"",
"for (var i = 10; i > 0; i -= 2) {",
" ourArray.push(i);",
"}",
"",
"// Setup",
"var myArray = [];",
"",
"// Only change code below this line.",
""
],
"tail": [
"if(typeof myArray !== \"undefined\"){(function(){return myArray;})();}"
],
"solutions": [
"var ourArray = [];\nfor (var i = 10; i > 0; i -= 2) {\n ourArray.push(i);\n}\nvar myArray = [];\nfor (var i = 9; i > 0; i -= 2) {\n myArray.push(i);\n}"
],
"tests": [
"assert(code.match(/for\\s*\\(/g).length > 1, 'message: You should be using a for loop for this.');",
"assert.deepEqual(myArray, [9,7,5,3,1], 'message: myArray should equal [9,7,5,3,1].');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Cuenta hacia atrás con un ciclo for",
"descriptionEs": [
"Un ciclo también puede contar hacia atrás, siempre y cuando definamos las condiciones adecuadas.",
"Para contar hacia atrás de dos en dos, tendremos que cambiar nuestra inicialización, la condición y la última-expresión.",
"Vamos a empezar con i = 10 e iteraremos mientras i > 0. Vamos a decrementar i de a 2 por cada iteración con i -= 2. ",
"var ourArray = [];",
"for (var i = 10; i > 0; i -= 2) {",
" ourArray.push(i);",
"}",
"ourArray ahora contendrá [10,8,6,4,2].",
"Vamos a cambiar nuestra inicialización y la expresión final para que podamos contar hacia atrás de dos en dos pero números impares.",
"Empuja los números impares del 9 a 1 en myArray utilizando un ciclo for."
]
},
{
"id": "5675e877dbd60be8ad28edc6",
"title": "Iterate Through an Array with a For Loop",
"description": [
"A common task in Javascript is to iterate through the contents of an array. One way to do that is with a for loop. This code will output each element of the array arr to the console:",
"
var arr = [10,9,8,7,6]; for (var i=0; i < arr.length; i++) { console.log(arr[i]); }
",
"Remember that Arrays have zero-based numbering, which means the last index of the array is length - 1. Our condition for this loop is i < arr.length, which stops when i is at length - 1.",
"
Instructions
",
"Declare and initialize a variable total to 0. Use a for loop to add the value of each element of the myArr array to total."
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"// Example",
"var ourArr = [ 9, 10, 11, 12];",
"var ourTotal = 0;",
"",
"for (var i = 0; i < ourArr.length; i++) {",
" ourTotal += ourArr[i];",
"}",
"",
"// Setup",
"var myArr = [ 2, 3, 4, 5, 6];",
"",
"// Only change code below this line",
"",
""
],
"tail": [
"(function(){if(typeof total !== 'undefined') { return \"total = \" + total; } else { return \"total is undefined\";}})()"
],
"solutions": [
"var myArr = [ 2, 3, 4, 5, 6];\nvar total = 0;\n\nfor (var i = 0; i < myArr.length; i++) {\n total += myArr[i];\n}"
],
"tests": [
"assert(code.match(/var\\s*total\\s*=\\s*0\\s*;/), 'message: total should be declared and initialized to 0');",
"assert(total === 20, 'message: total should equal 20');",
"assert(code.match(/for\\s*\\((.*?)myArr\\.length/), 'message: You should use a for loop to iterate through myArr.');",
"assert(!code.match(/total[\\s\\+\\-]*=\\s*(\\d(?!\\s*;)|[1-9])/g), 'message: Do not set total to 20 directly');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "56533eb9ac21ba0edf2244e1",
"title": "Nesting For Loops",
"description": [
"If you have a multi-dimensional array, you can use the same logic as the prior waypoint to loop through both the array and any sub-arrays. Here is an example:",
"
var arr = [ [1,2], [3,4], [5,6] ]; for (var i=0; i < arr.length; i++) { for (var j=0; j < arr[i].length; j++) { console.log(arr[i][j]); } }
",
"This outputs each sub-element in arr one at a time. Note that for the inner loop, we are checking the .length of arr[i], since arr[i] is itself an array.",
"
Instructions
",
"Modify function multiplyAll so that it multiplies the product variable by each number in the sub-arrays of arr"
],
"releasedOn": "January 1, 2016",
"challengeSeed": [
"function multiplyAll(arr) {",
" var product = 1;",
" // Only change code below this line",
" ",
" // Only change code above this line",
" return product;",
"}",
"",
"// Modify values below to test your code",
"multiplyAll([[1,2],[3,4],[5,6,7]]);",
""
],
"tail": [
""
],
"solutions": [
"function multiplyAll(arr) {\n var product = 1;\n for (var i = 0; i < arr.length; i++) {\n for (var j = 0; j < arr[i].length; j++) {\n product *= arr[i][j];\n }\n }\n return product;\n}\n\nmultiplyAll([[1,2],[3,4],[5,6,7]]);"
],
"tests": [
"assert(multiplyAll([[1],[2],[3]]) === 6, 'message: multiplyAll([[1],[2],[3]]); should return 6');",
"assert(multiplyAll([[1,2],[3,4],[5,6,7]]) === 5040, 'message: multiplyAll([[1,2],[3,4],[5,6,7]]) should return 5040');",
"assert(multiplyAll([[5,1],[0.2, 4, 0.5],[3, 9]]) === 54, 'message: multiplyAll([[5,1],[0.2, 4, 0.5],[3, 9]]);) should return 54');"
],
"type": "waypoint",
"challengeType": 1
},
{
"id": "cf1111c1c11feddfaeb1bdef",
"title": "Iterate with JavaScript While Loops",
"description": [
"You can run the same code multiple times by using a loop.",
"Another type of JavaScript loop is called a \"while loop\", because it runs \"while\" a specified condition is true and stops once that condition is no longer true.",
"
var ourArray = []; var i = 0; while(i < 5) { ourArray.push(i); i++; }
",
"Let's try getting a while loop to work by pushing values to an array.",
"
Instructions
",
"Push the numbers 0 through 4 to myArray using a while loop."
],
"challengeSeed": [
"// Setup",
"var myArray = [];",
"",
"// Only change code below this line.",
"",
""
],
"tail": [
"if(typeof myArray !== \"undefined\"){(function(){return myArray;})();}"
],
"solutions": [
"var myArray = [];\nvar i = 0;\nwhile(i < 5) {\n myArray.push(i);\n i++;\n}"
],
"tests": [
"assert(code.match(/while/g), 'message: You should be using a while loop for this.');",
"assert.deepEqual(myArray, [0,1,2,3,4], 'message: myArray should equal [0,1,2,3,4].');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Iterar con JavaScript con ciclos while",
"descriptionEs": [
"Puede ejecutar el mismo código varias veces mediante el uso de un ciclo.",
"Otro tipo de ciclo de JavaScript se llama un ciclo \"while\", ya que se ejecuta, \"mientras que\" algo sea cierto y se detiene una vez que ya no sea así.",
"var ourArray = [];",
"var i = 0;",
"while(i < 5) {",
" ourArray.push(i);",
" i++;",
"}",
"Intentemos que un ciclo while empuje valores en un vector.",
"Empuja los números de 0 a 4 para myArray utilizando un ciclo while."
]
},
{
"id": "5688e62ea601b2482ff8422b",
"title": "Profile Lookup",
"description": [
"We have an array of objects representing different people in our contacts lists.",
"A lookUp function that takes firstName and a property (prop) as arguments has been pre-written for you.",
"The function should check if firstName is an actual contact's firstName and the given property (prop) is a property of that contact.",
"If both are true, then return the \"value\" of that property.",
"If firstName does not correspond to any contacts then return \"No such contact\"",
"If prop does not correspond to any valid properties then return \"No such property\"",
""
],
"releasedOn": "January 8, 2016",
"challengeSeed": [
"//Setup",
"var contacts = [",
" {",
" \"firstName\": \"Akira\",",
" \"lastName\": \"Laine\",",
" \"number\": \"0543236543\",",
" \"likes\": [\"Pizza\", \"Coding\", \"Brownie Points\"]",
" },",
" {",
" \"firstName\": \"Harry\",",
" \"lastName\": \"Potter\",",
" \"number\": \"0994372684\",",
" \"likes\": [\"Hogwarts\", \"Magic\", \"Hagrid\"]",
" },",
" {",
" \"firstName\": \"Sherlock\",",
" \"lastName\": \"Holmes\",",
" \"number\": \"0487345643\",",
" \"likes\": [\"Intriguing Cases\", \"Violin\"]",
" },",
" {",
" \"firstName\": \"Kristian\",",
" \"lastName\": \"Vos\",",
" \"number\": \"unknown\",",
" \"likes\": [\"Javascript\", \"Gaming\", \"Foxes\"]",
" }",
"];",
"",
"",
"function lookUp(firstName, prop){",
"// Only change code below this line",
"",
"// Only change code above this line",
"}",
"",
"// Change these values to test your function",
"lookUp(\"Akira\", \"likes\");"
],
"solutions": [
"var contacts = [\n {\n \"firstName\": \"Akira\",\n \"lastName\": \"Laine\",\n \"number\": \"0543236543\",\n \"likes\": [\"Pizza\", \"Coding\", \"Brownie Points\"]\n },\n {\n \"firstName\": \"Harry\",\n \"lastName\": \"Potter\",\n \"number\": \"0994372684\",\n \"likes\": [\"Hogwarts\", \"Magic\", \"Hagrid\"]\n },\n {\n \"firstName\": \"Sherlock\",\n \"lastName\": \"Holmes\",\n \"number\": \"0487345643\",\n \"likes\": [\"Intriguing Cases\", \"Violin\"]\n },\n {\n \"firstName\": \"Kristian\",\n \"lastName\": \"Vos\",\n \"number\": \"unknown\",\n \"likes\": [\"Javascript\", \"Gaming\", \"Foxes\"]\n },\n];\n\n\n//Write your function in between these comments\nfunction lookUp(name, prop){\n for(var i in contacts){\n if(contacts[i].firstName === name) {\n return contacts[i][prop] || \"No such property\";\n }\n }\n return \"No such contact\";\n}\n//Write your function in between these comments\n\nlookUp(\"Akira\", \"likes\");"
],
"tests": [
"assert(lookUp('Kristian','lastName') === \"Vos\", 'message: \"Kristian\", \"lastName\" should return \"Vos\"');",
"assert.deepEqual(lookUp(\"Sherlock\", \"likes\"), [\"Intriguing Cases\", \"Violin\"], 'message: \"Sherlock\", \"likes\" should return [\"Intriguing Cases\", \"Violin\"]');",
"assert(typeof lookUp(\"Harry\", \"likes\") === \"object\", 'message: \"Harry\",\"likes\" should return an array');",
"assert(lookUp(\"Bob\", \"number\") === \"No such contact\", 'message: \"Bob\", \"number\" should return \"No such contact\"');",
"assert(lookUp(\"Akira\", \"address\") === \"No such property\", 'message: \"Akira\", \"address\" should return \"No such property\"');"
],
"type": "checkpoint",
"challengeType": 1
},
{
"id": "cf1111c1c11feddfaeb9bdef",
"title": "Generate Random Fractions with JavaScript",
"description": [
"Random numbers are useful for creating random behavior.",
"JavaScript has a Math.random() function that generates a random decimal number between 0 (inclusive) and not quite up to 1 (exclusive). Thus Math.random() can return a 0 but never quite return a 1",
"Note Like Storing Values with the Equal Operator, all function calls will be resolved before the return executes, so we can simply return the value of the Math.random() function.",
"
Instructions
",
"Change myFunction to return a random number instead of returning 0."
],
"challengeSeed": [
"function myFunction() {",
"",
" // Only change code below this line.",
"",
" return 0;",
"",
" // Only change code above this line.",
"}"
],
"tail": [
"(function(){return myFunction();})();"
],
"solutions": [
"function myFunction() {\n return Math.random();\n}"
],
"tests": [
"assert(typeof myFunction() === \"number\", 'message: myFunction should return a random number.');",
"assert((myFunction()+''). match(/\\./g), 'message: The number returned by myFunction should be a decimal.');",
"assert(code.match(/Math\\.random/g).length >= 0, 'message: You should be using Math.random to generate the random decimal number.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Generar fracciones al azar con JavaScript",
"descriptionEs": [
"Los números aleatorios son útiles para crear un comportamiento aleatorio.",
"JavaScript tiene una función Math.random() que genera un número decimal aleatorio.",
"Cambia myFunction para que devuelva un número al azar en lugar de devolver 0.",
"Ten en cuenta que puedes retornar lo retornado por una función, igual que harías para devolver una variable o valor."
]
},
{
"id": "cf1111c1c12feddfaeb1bdef",
"title": "Generate Random Whole Numbers with JavaScript",
"description": [
"It's great that we can generate random decimal numbers, but it's even more useful if we use it to generate random whole numbers.",
"
Use Math.random() to generate a random decimal.
Multiply that random decimal by 20.
Use another function, Math.floor() to round the number down to its nearest whole number.
",
"Remember that Math.random() can never quite return a 1 and, because we're rounding down, it's impossible to actually get 20. This technique will give us a whole number between 0 and 19.",
"Putting everything together, this is what our code looks like:",
"Math.floor(Math.random() * 20);",
"We are calling Math.random(), multiplying the result by 20, then passing the value to Math.floor() function to round the value down to the nearest whole number.",
"
Instructions
",
"Use this technique to generate and return a random whole number between 0 and 9."
],
"challengeSeed": [
"var randomNumberBetween0and19 = Math.floor(Math.random() * 20);",
"",
"function myFunction() {",
"",
" // Only change code below this line.",
"",
" return Math.random();",
"}"
],
"tail": [
"(function(){return myFunction();})();"
],
"solutions": [
"var randomNumberBetween0and19 = Math.floor(Math.random() * 20);\n\nfunction myFunction() {\n return Math.floor(Math.random() * 10);\n}"
],
"tests": [
"assert(typeof myFunction() === \"number\" && (function(){var r = myFunction();return Math.floor(r) === r;})(), 'message: The result of myFunction should be a whole number.');",
"assert(code.match(/Math.random/g).length > 1, 'message: You should be using Math.random to generate a random number.');",
"assert(code.match(/\\(\\s*?Math.random\\s*?\\(\\s*?\\)\\s*?\\*\\s*?10\\s*?\\)/g) || code.match(/\\(\\s*?10\\s*?\\*\\s*?Math.random\\s*?\\(\\s*?\\)\\s*?\\)/g), 'message: You should have multiplied the result of Math.random by 10 to make it a number that is between zero and nine.');",
"assert(code.match(/Math.floor/g).length > 1, 'message: You should use Math.floor to remove the decimal part of the number.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Genera números aleatorios enteros con JavaScript",
"descriptionEs": [
"Es muy bueno que podamos generar números decimales al azar, pero es aún más útil si lo utilizamos para generar números enteros aleatorios.",
"En primer lugar, vamos a usar Math.random() para generar un decimal aleatorio.",
"Entonces vamos a multiplicar este decimal azar por 20.",
"Por último, vamos a usar otra función, Math.floor() para redondear el número hasta su número entero más próximo.",
"Esta técnica nos da un número entero entre 0 y 19.",
"Tenga en cuenta que debido a que estamos redondeando, es imposible obtener 20.",
"Poniendo todo junto, así es como se ve nuestro código:",
"Math.floor(Math.random() * 20);",
"¿Ves como Math.floor toma (Math.random() * 20) como su argumento? Así es - puedes pasar el resultado de un función como argumento de otra función.",
"usemos esta técnica para generar y devolver un número entero aleatorio entre 0 y 9."
]
},
{
"id": "cf1111c1c12feddfaeb2bdef",
"title": "Generate Random Whole Numbers within a Range",
"description": [
"Instead of generating a random number between zero and a given number like we did before, we can generate a random number that falls within a range of two specific numbers.",
"To do this, we'll define a minimum number min and a maximum number max.",
"Here's the formula we'll use. Take a moment to read it and try to understand what this code is doing:",
"Math.floor(Math.random() * (max - min + 1)) + min",
"
Instructions
",
"Create a function called randomRange that takes a range myMin and myMax and returns a random number that's greater than or equal to myMin, and is less than or equal to myMax, inclusive."
],
"challengeSeed": [
"// Example",
"function ourFunction(ourMin, ourMax) {",
"",
" return Math.floor(Math.random() * (ourMax - ourMin + 1)) + ourMin;",
"}",
"",
"ourFunction(1, 9);",
"",
"// Only change code below this line.",
"",
"function randomRange(myMin, myMax) {",
"",
" return 0; // Change this line",
"",
"}",
"",
"// Change these values to test your function",
"var myRandom = randomRange(5, 15);"
],
"tail": [
"var calcMin = 100;",
"var calcMax = -100;",
"for(var i = 0; i < 100; i++) {",
" var result = randomRange(5,15);",
" calcMin = Math.min(calcMin, result);",
" calcMax = Math.max(calcMax, result);",
"}",
"(function(){",
" if(typeof myRandom === 'number') {",
" return \"myRandom = \" + myRandom;",
" } else {",
" return \"myRandom undefined\";",
" }",
"})();"
],
"solutions": [
"function randomRange(myMin, myMax) {\n return Math.floor(Math.random() * (myMax - myMin + 1)) + myMin;\n}"
],
"tests": [
"assert(calcMin === 5, 'message: The random number generated by randomRange should be greater than or equal to your minimum number, myMin.');",
"assert(calcMax === 15, 'message: The random number generated by randomRange should be less than or equal to your maximum number, myMax.');",
"assert(randomRange(0,1) % 1 === 0 , 'message: The random number generated by randomRange should be an integer, not a decimal.');",
"assert((function(){if(code.match(/myMax/g).length > 1 && code.match(/myMin/g).length > 2 && code.match(/Math.floor/g) && code.match(/Math.random/g)){return true;}else{return false;}})(), 'message: randomRange should use both myMax and myMin, and return a random number in your range.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Genera números aleatorios enteros dentro de un rango",
"descriptionEs": [
"En lugar de generar un número aleatorio entre cero y un número dado como lo hicimos antes, podemos generar un número aleatorio que caiga dentro de un rango de dos números específicos.",
"Para ello, vamos a definir un número mínimo min y un número máximo max.",
"He aquí la fórmula que utilizaremos. Tómate un momento para leer y tratar de entender lo que el código está haciendo: ",
"Math.floor(Math.random() * (max - min + 1)) + min",
"Definir dos variables: myMin y myMax, y asignales valores enteros.",
"A continuación, crea una función llamada myFunction que devuelva un número aleatorio mayor o igual a myMin, y menor o igual a myMax. "
]
},
{
"id": "cf1111c1c12feddfaeb6bdef",
"title": "Sift through Text with Regular Expressions",
"description": [
"Regular expressions are used to find certain words or patterns inside of strings.",
"For example, if we wanted to find the word the in the string The dog chased the cat, we could use the following regular expression: /the/gi",
"Let's break this down a bit:",
"/ is the start of the regular expression.",
"the is the pattern we want to match.",
"/ is the end of the regular expression.",
"g means global, which causes the pattern to return all matches in the string, not just the first one.",
"i means that we want to ignore the case (uppercase or lowercase) when searching for the pattern.",
"
Instructions
",
"Select all the occurrences of the word and in testString.",
"You can do this by replacing the . part of the regular expression with the word and."
],
"head": [
""
],
"challengeSeed": [
"// Setup",
"var testString = \"Ada Lovelace and Charles Babbage designed the first computer and the software that would have run on it.\";",
"",
"// Example",
"var expressionToGetSoftware = /software/gi;",
"var softwareCount = testString.match(expressionToGetSoftware).length;",
" ",
"",
"// Only change code below this line.",
"",
"var expression = /./gi; // Change this Line",
"",
"// Only change code above this line",
"",
"// This code counts the matches of expression in testString",
"var andCount = testString.match(expression).length;",
""
],
"tail": [
"(function(){return andCount;})();"
],
"solutions": [
"var testString = \"Ada Lovelace and Charles Babbage designed the first computer and the software that would have run on it.\";\nvar expression = /and/gi; // Change this Line\nvar andCount = testString.match(expression).length;"
],
"tests": [
"assert(andCount==2, 'message: Your regular expression should find two occurrences of the word and.');",
"assert(code.match(/\\/and\\/gi/), 'message: Use regular expressions to find the word and in testString.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Examina un texto con expresiones regulares",
"descriptionEs": [
"Las expresiones regulares se utilizan para encontrar ciertas palabras o patrones dentro de cadenas.",
"Por ejemplo, si quisiéramos encontrar la palabra el en la cadena El perro persiguió al gato el lunes, podríamos utilizar la siguiente expresión regular: /el/gi ",
"Vamos a dividirla un poco:",
"el es el patrón con el que queremos coincidir.",
"g significa que queremos buscar el patrón en toda la cadena y no sólo la primera ocurrencia.",
"i significa que queremos ignorar la capitalización (en mayúsculas o minúsculas) cuando se busque el patrón.",
"Las expresiones regulares se escriben rodeando el patrón con símbolos de barra /.",
"Vamos a tratar de seleccionar todas las apariciones de la palabra and en la cadena Ada Lovelace and Charles Babbage designed the first computer and the software that would have run on it.",
"Podemos hacer esto sustituyendo la parte . de nuestra expresión regular por la palabra and."
]
},
{
"id": "cf1111c1c12feddfaeb7bdef",
"title": "Find Numbers with Regular Expressions",
"description": [
"We can use special selectors in Regular Expressions to select a particular type of value.",
"One such selector is the digit selector \\d which is used to retrieve one digit (e.g. numbers 0 to 9) in a string.",
"In JavaScript, it is used like this: /\\d/g.",
"Appending a plus sign (+) after the selector, e.g. /\\d+/g, allows this regular expression to match one or more digits.",
"The trailing g is short for 'global', which allows this regular expression to find all matches rather than stop at the first match.",
"
Instructions
",
"Use the \\d selector to select the number of numbers in the string, allowing for the possibility of one or more digit."
],
"head": [
""
],
"challengeSeed": [
"// Setup",
"var testString = \"There are 3 cats but 4 dogs.\";",
"",
"// Only change code below this line.",
"",
"var expression = /.+/g; // Change this line",
"",
"// Only change code above this line",
"",
"// This code counts the matches of expression in testString",
"var digitCount = testString.match(expression).length;"
],
"tail": [
"(function(){return digitCount;})();"
],
"solutions": [
"var testString = \"There are 3 cats but 4 dogs.\";\nvar expression = /\\d+/g; // Change this line\nvar digitCount = testString.match(expression).length;"
],
"tests": [
"assert(digitCount === 2, 'message: Your regular expression should find two numbers in testString.');",
"assert(code.match(/\\/\\\\d\\+\\//g), 'message: Use the /\\d+/g regular expression to find the numbers in testString.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Encuentra números con expresiones regulares",
"descriptionEs": [
"Podemos usar selectores especiales en las expresiones regulares para seleccionar un determinado tipo de valor.",
"Uno de estos selectores es el de dígitos \\d que se utiliza para hacer coincidir números en una cadena.",
"Se usa así para hacer coincidir un dígito: /\\d/g.",
"Para hacer coincidir números de varios dígtios a menudo se escribe /\\d+/ g , donde el + que sigue al selector de dígito le permite a la expresión regular coincidir con uno o más dígito es decir coincide con números de varios dígitos.",
"Usa el selector \\d para hacer coincidir todos los números de la cadena, permitiendo la posibilidad de hacer coincidir números de varios dígitos."
]
},
{
"id": "cf1111c1c12feddfaeb8bdef",
"title": "Find Whitespace with Regular Expressions",
"description": [
"We can also use regular expression selectors like \\s to find whitespace in a string.",
"The whitespace characters are \" \" (space), \\r (the carriage return), \\n (newline), \\t (tab), and \\f (the form feed).",
"The whitespace regular expression looks like this:",
"/\\s+/g",
"
Instructions
",
"Use \\s to select all the whitespace characters in the sentence string."
],
"head": [
""
],
"challengeSeed": [
"// Setup",
"var testString = \"How many spaces are there in this sentence?\";",
"",
"// Only change code below this line.",
"",
"var expression = /.+/g; // Change this line",
"",
"// Only change code above this line",
"",
"// This code counts the matches of expression in testString",
"var spaceCount = testString.match(expression).length;"
],
"tail": [
"(function(){return spaceCount;})();"
],
"solutions": [
"var testString = \"How many spaces are there in this sentence?\";\nvar expression = /\\s+/g; // Change this line\nvar spaceCount = testString.match(expression).length;"
],
"tests": [
"assert(spaceCount === 7, 'message: Your regular expression should find seven spaces in testString.');",
"assert(code.match(/\\/\\\\s\\+\\//g), 'message: Use the /\\s+/g regular expression to find the spaces in testString.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Encuentra espacios en blanco con las expresiones regulares",
"descriptionEs": [
"También podemos utilizar selectores de expresiones regulares como \\s para encontrar un espacio en blanco en una cadena.",
"Los espacios en blanco son \" \" (espacio), \\r (el retorno de carro), \\n (nueva línea), \\t (tabulador), y \\f (el avance de página). ",
"Una expresión regular con el selector de espacios en blanco puede ser:",
"/\\s+/g",
"Se usa para hacer coincidir todos los espacios en blanco en una cadena."
]
},
{
"id": "cf1111c1c13feddfaeb3bdef",
"title": "Invert Regular Expression Matches with JavaScript",
"description": [
"You can invert any match by using the uppercase version of the regular expression selector.",
"For example, \\s will match any whitespace, and \\S will match anything that isn't whitespace.",
"
Instructions
",
"Use /\\S/g to count the number of non-whitespace characters in testString."
],
"head": [
""
],
"challengeSeed": [
"// Setup",
"var testString = \"How many non-space characters are there in this sentence?\";",
"",
"// Only change code below this line.",
"",
"var expression = /.+/g; // Change this line",
"",
"// Only change code above this line",
"",
"// This code counts the matches of expression in testString",
"var nonSpaceCount = testString.match(expression).length;"
],
"tail": [
"(function(){return nonSpaceCount;})();"
],
"solutions": [
"var testString = \"How many non-space characters are there in this sentence?\";\nvar expression = /\\S/g; \nvar nonSpaceCount = testString.match(expression).length;"
],
"tests": [
"assert(nonSpaceCount === 49, 'message: Your regular expression should find forty nine non-space characters in the testString.');",
"assert(code.match(/\\/\\\\S\\/g/g), 'message: Use the /\\S/g regular expression to find non-space characters in testString.');"
],
"type": "waypoint",
"challengeType": 1,
"nameEs": "Hacer coincidir con una expresión regular invertida",
"descriptionEs": [
"Puedes invertir las coincidencias de un selector usando su versión en mayúsculas.",
"Por ejemplo, \\s coincidirá con cualquier espacio en blanco, mientras que \\S coincidirá con todo lo que no sea espacio en blanco.",
"Usa /\\S/g para contar el número de caracteres que no están en blanco en testString."
]
},
{
"id": "cf1111c1c12feddfaeb9bdef",
"title": "Create a JavaScript Slot Machine",
"description": [
"We are now going to try and combine some of the stuff we've just learned and create the logic for a slot machine game.",
"For this we will need to generate three random numbers between 1 and 3 to represent the possible values of each individual slot.",
"Store the three random numbers in slotOne, slotTwo and slotThree.",
"Generate the random numbers by using the system we used earlier (an explanation of the formula can be found here):",
"Math.floor(Math.random() * (3 - 1 + 1)) + 1;"
],
"challengeSeed": [
"fccss",
" function runSlots() {",
" var slotOne;",
" var slotTwo;",
" var slotThree;",
" ",
" var images = [\"http://i.imgur.com/9H17QFk.png\", \"http://i.imgur.com/9RmpXTy.png\", \"http://i.imgur.com/VJnmtt5.png\"];",
" ",
" // Only change code below this line.",
" ",
" ",
" ",
" // Only change code above this line.",
" ",
" ",
" if (slotOne !== undefined && slotTwo !== undefined && slotThree !== undefined) {",
" $(\".logger\").html(slotOne + \" \" + slotTwo + \" \" + slotThree);",
" }",
" ",
" ",
" $(\".logger\").append(\" Not A Win\")",
" return [slotOne, slotTwo, slotThree];",
" }",
"",
" $(document).ready(function() {",
" $(\".go\").click(function() {",
" runSlots();",
" });",
" });",
"fcces",
" ",
"
",
"
",
"
",
" ",
"
FCC Slot Machine
",
"
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" ",
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" ",
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" ",
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" ",
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" ",
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" ",
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"",
""
],
"solutions": [
""
],
"tests": [
"assert(typeof(runSlots($(\".slot\"))[0]) === \"number\" && runSlots($(\".slot\"))[0] > 0 && runSlots($(\".slot\"))[0] < 4, 'slotOne should be a random number.')",
"assert(typeof(runSlots($(\".slot\"))[1]) === \"number\" && runSlots($(\".slot\"))[1] > 0 && runSlots($(\".slot\"))[1] < 4, 'slotTwo should be a random number.')",
"assert(typeof(runSlots($(\".slot\"))[2]) === \"number\" && runSlots($(\".slot\"))[2] > 0 && runSlots($(\".slot\"))[2] < 4, 'slotThree should be a random number.')",
"assert((function(){if(editor.match(/Math\\.floor\\(\\s?Math\\.random\\(\\)\\s?\\*\\s?\\(\\s?3\\s?\\-\\s?1\\s?\\+\\s?1\\s?\\)\\s?\\)\\s?\\+\\s?1/gi) !== null){return editor.match(/slot.*?=.*?\\(.*?\\).*?/gi).length >= 3;}else{return false;}})(), 'You should have used Math.floor(Math.random() * (3 - 1 + 1)) + 1; three times to generate your random numbers.')"
],
"type": "waypoint",
"challengeType": 0,
"isBeta": true,
"nameEs": "Crea una máquina tragamonedas en JavaScript",
"descriptionEs": [
"Ahora vamos a tratar de combinar algunas de las cosas que hemos aprendido para crear la lógica de una máquina tragamonedas.",
"Para esto tendremos que generar tres números aleatorios entre 1 y 3 que representen los valores posibles de cada casilla.",
"Guarda los tres números aleatorios en slotOne, slotTwo y slotThree.",
"Genera los números aleatorios utilizando el sistema que usamos anteriormente (puedes encontrar una explicación de la fórmula aquí):",
"Math.floor(Math.random() * (3 - 1 + 1)) + 1;"
]
},
{
"id": "cf1111c1c13feddfaeb1bdef",
"title": "Add your JavaScript Slot Machine Slots",
"description": [
"Now that our slots will each generate random numbers, we need to check whether they've all returned the same number.",
"If they have, we should notify our user that they've won and we should return null.",
"null is a JavaScript data structure that means nothing.",
"The user wins when all the three numbers match. Let's create an if statement with multiple conditions in order to check whether all numbers are equal.",
"if (slotOne === slotTwo && slotTwo === slotThree){",
" return null;",
"}",
"Also, we need to show the user that he has won the game when he gets the same number in all the slots.",
"If all three numbers match, we should also set the text \"It's A Win\" to the element with class logger."
],
"challengeSeed": [
"fccss",
" function runSlots() {",
" var slotOne;",
" var slotTwo;",
" var slotThree;",
" ",
" var images = [\"http://i.imgur.com/9H17QFk.png\", \"http://i.imgur.com/9RmpXTy.png\", \"http://i.imgur.com/VJnmtt5.png\"];",
" ",
" slotOne = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" slotTwo = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" slotThree = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" ",
" ",
" // Only change code below this line.",
" ",
" ",
" ",
" // Only change code above this line.",
" ",
" if (slotOne !== undefined && slotTwo !== undefined && slotThree !== undefined){",
" $(\".logger\").html(slotOne + \" \" + slotTwo + \" \" + slotThree);",
" }",
" ",
" $(\".logger\").append(\" Not A Win\");",
" ",
" return [slotOne, slotTwo, slotThree];",
" }",
"",
" $(document).ready(function() {",
" $(\".go\").click(function() {",
" runSlots();",
" });",
" });",
"fcces",
" ",
"
",
"
",
"
",
" ",
"
FCC Slot Machine
",
"
",
"
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"
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" ",
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" ",
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" ",
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" ",
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" ",
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" ",
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" ",
"
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"
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"
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"",
""
],
"solutions": [
""
],
"tests": [
"assert((function(){var data = runSlots();return data === null || data.toString().length === 1;})(), 'If all three of our random numbers are the same we should return that number. Otherwise we should return null.')"
],
"type": "waypoint",
"challengeType": 0,
"isBeta": true,
"nameEs": "Añade casillas a tu tragamonedas JavaScript",
"descriptionEs": [
"Ahora que cada una de nuestras casillas genera números aleatorios, tenemos que comprobar si todos quedan con el mismo número.",
"Si es así, debemos notificar a nuestros usuarios que han ganado y debemos retornar null.",
"null es una estructura de datos de JavaScript que significa \"nada\".",
"El usuario gana cuando los tres números coinciden. Cremos una instrucción if con varias condiciones, a fin de comprobar si todos los números son iguales. ",
"if(slotOne === slotTwo && slotTwo === slotThree){",
" return null;",
"}",
"Además, tenemos que mostrar al usuario que ha ganado la partida e caso de que esté el mismo número en todas las casillas.",
"Si los tres números coinciden, también hay que poner el texto \"It's A Win\" en el elemento HTML con clase logger."
]
},
{
"id": "cf1111c1c13feddfaeb2bdef",
"title": "Bring your JavaScript Slot Machine to Life",
"description": [
"Now we can detect a win. Let's get this slot machine working.",
"Let's use the jQuery selector$(\".slot\") to select all of the slots.",
"Once they are all selected, we can use bracket notation to access each individual slot:",
"$($(\".slot\")[0]).html(slotOne);",
"This jQuery will select the first slot and update it's HTML to display the correct number.",
"Use the above selector to display each number in its corresponding slot."
],
"challengeSeed": [
"fccss",
" function runSlots() {",
" var slotOne;",
" var slotTwo;",
" var slotThree;",
" ",
" var images = [\"http://i.imgur.com/9H17QFk.png\", \"http://i.imgur.com/9RmpXTy.png\", \"http://i.imgur.com/VJnmtt5.png\"];",
" ",
" slotOne = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" slotTwo = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" slotThree = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" ",
" ",
" // Only change code below this line.",
" ",
" ",
" ",
" // Only change code above this line.",
" ",
" if (slotOne === slotTwo && slotTwo === slotThree) {",
" $(\".logger\").html(\" It's A Win\")",
" return null;",
" }",
" ",
" if (slotOne !== undefined && slotTwo !== undefined && slotThree !== undefined){",
" $(\".logger\").html(slotOne + \" \" + slotTwo + \" \" + slotThree);",
" }",
" ",
" $(\".logger\").append(\" Not A Win\");",
" ",
" ",
" return [slotOne, slotTwo, slotThree];",
" }",
"",
" $(document).ready(function() {",
" $(\".go\").click(function() {",
" runSlots();",
" });",
" });",
"fcces",
" ",
"
",
"
",
"
",
" ",
"
FCC Slot Machine
",
"
",
"
",
"
",
" ",
"
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" ",
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" ",
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" ",
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" ",
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" ",
"
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" ",
"
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"
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"
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"",
""
],
"solutions": [
""
],
"tests": [
"assert((function(){runSlots();if($($(\".slot\")[0]).html().replace(/\\s/gi, \"\") !== \"\" && $($(\".slot\")[1]).html().replace(/\\s/gi, \"\") !== \"\" && $($(\".slot\")[2]).html().replace(/\\s/gi, \"\") !== \"\"){return true;}else{return false;}})(), 'You should be displaying the result of the slot numbers in the corresponding slots.')",
"assert((editor.match( /\\$\\s*?\\(\\s*?\\$\\s*?\\(\\s*?(?:'|\")\\s*?\\.slot\\s*?(?:'|\")\\s*?\\)\\[\\d\\]\\s*?\\)/gi) && editor.match( /\\$\\s*?\\(\\s*?\\$\\s*?\\(\\s*?(?:'|\")\\s*?\\.slot\\s*?(?:'|\")\\s*?\\)\\[\\d\\]\\s*?\\)/gi ).length >= 3 && editor.match( /\\.html\\(slotOne\\)/gi ) && editor.match( /\\.html\\(slotTwo\\)/gi ) && editor.match( /\\.html\\(slotThree\\)/gi )), 'You should have used the the selector given in the description to select each slot and assign it the value of slotOne, slotTwo and slotThree respectively.')"
],
"type": "waypoint",
"challengeType": 0,
"isBeta": true,
"nameEs": "Da vida a tu máquina tragamonedas en JavaScript",
"descriptionEs": [
"Ahora podemos detectar una victoria. Logremos que la máquina tragamonedas funcione. ",
"Usemos un selector de jQuery $(\".slot\") para seleccionar todas las casillas.",
"Una vez que todas estén seleccionados, podemos usar notación de corchetes para acceder a cada casilla individual:",
"$($(\".slot\")[0]).html(slotOne);",
"Este jQuery seleccionará la primera ranura y actualizará su HTML para mostrar el número correcto.",
"Usa el selector anterior para mostrar cada número en su casilla correspondiente."
]
},
{
"id": "cf1111c1c11feddfaeb1bdff",
"title": "Give your JavaScript Slot Machine some Stylish Images",
"description": [
"Now let's add some images to our slots.",
"We've already set up the images for you in an array called images. We can use different indexes to grab each of these.",
"Here's how we would set the first slot to show a different image depending on which number its random number generates:",
"$($('.slot')[0]).html('<img src = \"' + images[slotOne-1] + '\">');",
"Set up all three slots like this, then click the \"Go\" button to play the slot machine."
],
"challengeSeed": [
"fccss",
" function runSlots() {",
" var slotOne;",
" var slotTwo;",
" var slotThree;",
" ",
" var images = [\"http://i.imgur.com/9H17QFk.png\", \"http://i.imgur.com/9RmpXTy.png\", \"http://i.imgur.com/VJnmtt5.png\"];",
" ",
" slotOne = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" slotTwo = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" slotThree = Math.floor(Math.random() * (3 - 1 + 1)) + 1;",
" ",
" ",
" // Only change code below this line.",
" ",
" ",
" ",
" // Only change code above this line.",
" ",
" if (slotOne === slotTwo && slotTwo === slotThree) {",
" $('.logger').html(\"It's A Win\");",
" return null;",
" }",
" ",
" if (slotOne !== undefined && slotTwo !== undefined && slotThree !== undefined){",
" $(\".logger\").html(slotOne + \" \" + slotTwo + \" \" + slotThree);",
" }",
" ",
" $('.logger').append(\" Not A Win\");",
" ",
" return [slotOne, slotTwo, slotThree];",
" }",
"",
" $(document).ready(function() {",
" $('.go').click(function() {",
" runSlots();",
" });",
" });",
"fcces",
" ",
"
",
"
",
"
",
" ",
"
FCC Slot Machine
",
"
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"
",
"
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" ",
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" ",
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" ",
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" ",
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" ",
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" ",
"
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" ",
"
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"
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"
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"",
""
],
"solutions": [
""
],
"tests": [
"assert((editor.match(/\\$\\s*?\\(\\s*?\\$\\s*?\\(\\s*?(?:'|\")\\s*?\\.slot\\s*?(?:'|\")\\s*?\\)\\[\\d\\]\\s*?\\)\\.html\\(\\s*?\\'\\\\'\\s*?\\);/gi) && editor.match(/\\$\\s*?\\(\\s*?\\$\\s*?\\(\\s*?(?:'|\")\\s*?\\.slot\\s*?(?:'|\")\\s*?\\)\\[\\d\\]\\s*?\\)\\.html\\(\\s*?\\'\\\\'\\s*?\\);/gi).length >= 3), 'Use the provided code three times. One for each slot.')",
"assert(editor.match(/\\$\\s*?\\(\\s*?\\$\\s*?\\(\\s*?(?:'|\")\\s*?\\.slot\\s*?(?:'|\")\\s*?\\)\\[0\\]\\s*?\\)/gi), 'You should have used $('.slot')[0] at least once.')",
"assert(editor.match(/\\$\\s*?\\(\\s*?\\$\\s*?\\(\\s*?(?:'|\")\\s*?\\.slot\\s*?(?:'|\")\\s*?\\)\\[1\\]\\s*?\\)/gi), 'You should have used $('.slot')[1] at least once.')",
"assert(editor.match(/\\$\\s*?\\(\\s*?\\$\\s*?\\(\\s*?(?:'|\")\\s*?\\.slot\\s*?(?:'|\")\\s*?\\)\\[2\\]\\s*?\\)/gi), 'You should have used $('.slot')[2] at least once.')",
"assert(editor.match(/slotOne/gi) && editor.match(/slotOne/gi).length >= 7, 'You should have used the slotOne value at least once.')",
"assert(editor.match(/slotTwo/gi) && editor.match(/slotTwo/gi).length >= 8, 'You should have used the slotTwo value at least once.')",
"assert(editor.match(/slotThree/gi) && editor.match(/slotThree/gi).length >= 7, 'You should have used the slotThree value at least once.')"
],
"type": "waypoint",
"challengeType": 0,
"isBeta": true,
"nameEs": "Dale a tu máquina tragamonedas JavaScript algunas imágenes con estilo",
"descriptionEs": [
"Ahora añadamos algunas imágenes en nuestras casillas.",
"Ya hemos creado las imágenes por ti en una matriz llamada images. Podemos utilizar diferentes índices para tomara cada una de estas. ",
"Aquí está como haríamos que la primera casilla muestre una imagen diferente dependiendo del número aleatorio que se genere:",
"$($('.slot')[0]).html('<img src = \"' + images[slotOne-1] + '\">');",
"Configura las tres casillas de manera análoga, a continuación, pulsa el botón \"Go\" para jugar con la máquina tragamonedas."
]
}
]
}
![\"learn](\"https://s3.amazonaws.com/freecodecamp/freecodecamp_logo.svg.gz\")
",
" 
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"