fix(learn): updated tests and deleted old sample code (#38450)

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/appending-variables-to-strings.english.md

@@ -85,10 +85,6 @@ var myStr = "Learning to code is ";
 
 
 ```js
-var anAdjective = "awesome!";
-var ourStr = "freeCodeCamp is ";
-ourStr += anAdjective;
-
 var someAdjective = "neat";
 var myStr = "Learning to code is ";
 myStr += someAdjective;

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/concatenating-strings-with-plus-operator.english.md

@@ -39,7 +39,7 @@ tests:
   - text: <code>myStr</code> should have a value of <code>This is the start. This is the end.</code>
     testString: assert(myStr === "This is the start. This is the end.");
   - text: You should use the <code>+</code> operator to build <code>myStr</code>.
-    testString: assert(code.match(/(["']).*(["'])\s*\+\s*(["']).*(["'])/g).length > 1);
+    testString: assert(code.match(/(["']).*\1\s*\+\s*(["']).*\2/g));
   - text: <code>myStr</code> should be created using the <code>var</code> keyword.
     testString: assert(/var\s+myStr/.test(code));
   - text: You should assign the result to the <code>myStr</code> variable.
@@ -84,7 +84,6 @@ var myStr; // Only change this line
 
 
 ```js
-var ourStr = "I come first. " + "I come second.";
 var myStr = "This is the start. " + "This is the end.";
 ```
 

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/concatenating-strings-with-the-plus-equals-operator.english.md

@@ -34,7 +34,7 @@ tests:
   - text: <code>myStr</code> should have a value of <code>This is the first sentence. This is the second sentence.</code>
     testString: assert(myStr === "This is the first sentence. This is the second sentence.");
   - text: You should use the <code>+=</code> operator to build <code>myStr</code>.
-    testString: assert(code.match(/\w\s*\+=\s*["']/g).length > 1 && code.match(/\w\s*\=\s*["']/g).length > 1);
+    testString: assert(code.match(/myStr\s*\+=\s*(["']).*\1/g));
 
 ```
 
@@ -79,9 +79,6 @@ var myStr;
 
 
 ```js
-var ourStr = "I come first. ";
-ourStr += "I come second.";
-
 var myStr = "This is the first sentence. ";
 myStr += "This is the second sentence.";
 ```

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/count-backwards-with-a-for-loop.english.md

@@ -34,7 +34,7 @@ Push the odd numbers from 9 through 1 to <code>myArray</code> using a <code>for<
 ```yml
 tests:
   - text: You should be using a <code>for</code> loop for this.
-    testString: assert(code.match(/for\s*\(/g).length > 1);
+    testString: assert(/for\s*\([^)]+?\)/.test(code));
   - text: You should be using the array method <code>push</code>.
     testString: assert(code.match(/myArray.push/));
   - text: <code>myArray</code> should equal <code>[9,7,5,3,1]</code>.
@@ -77,10 +77,6 @@ if(typeof myArray !== "undefined"){(function(){return myArray;})();}
 
 
 ```js
-var ourArray = [];
-for (var i = 10; i > 0; i -= 2) {
-  ourArray.push(i);
-}
 var myArray = [];
 for (var i = 9; i > 0; i -= 2) {
   myArray.push(i);

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/delete-properties-from-a-javascript-object.english.md

@@ -52,7 +52,7 @@ tests:
   - text: You should delete the property <code>"tails"</code> from <code>myDog</code>.
     testString: assert(typeof myDog === "object" && myDog.tails === undefined);
   - text: You should not modify the <code>myDog</code> setup.
-    testString: 'assert(code.match(/"tails": 1/g).length > 1);'
+    testString: 'assert(code.match(/"tails": 1/g).length > 0);'
 
 ```
 
@@ -97,13 +97,6 @@ var myDog = {
 
 
 ```js
-var ourDog = {
-  "name": "Camper",
-  "legs": 4,
-  "tails": 1,
-  "friends": ["everything!"],
-  "bark": "bow-wow"
-};
 var myDog = {
   "name": "Happy Coder",
   "legs": 4,

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/find-the-length-of-a-string.english.md

@@ -60,10 +60,6 @@ lastNameLength = lastName;
 
 
 ```js
-var firstNameLength = 0;
-var firstName = "Ada";
-firstNameLength = firstName.length;
-
 var lastNameLength = 0;
 var lastName = "Lovelace";
 lastNameLength = lastName.length;

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/iterate-odd-numbers-with-a-for-loop.english.md

@@ -33,7 +33,7 @@ Push the odd numbers from 1 through 9 to <code>myArray</code> using a <code>for<
 ```yml
 tests:
   - text: You should be using a <code>for</code> loop for this.
-    testString: assert(code.match(/for\s*\(/g).length > 1);
+    testString: assert(/for\s*\([^)]+?\)/.test(code));
   - text: <code>myArray</code> should equal <code>[1,3,5,7,9]</code>.
     testString: assert.deepEqual(myArray, [1,3,5,7,9]);
 
@@ -74,10 +74,6 @@ if(typeof myArray !== "undefined"){(function(){return myArray;})();}
 
 
 ```js
-var ourArray = [];
-for (var i = 0; i < 10; i += 2) {
-  ourArray.push(i);
-}
 var myArray = [];
 for (var i = 1; i < 10; i += 2) {
   myArray.push(i);

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/iterate-with-javascript-for-loops.english.md

@@ -38,7 +38,7 @@ Use a <code>for</code> loop to work to push the values 1 through 5 onto <code>my
 ```yml
 tests:
   - text: You should be using a <code>for</code> loop for this.
-    testString: assert(code.match(/for\s*\(/g).length > 1);
+    testString: assert(/for\s*\([^)]+?\)/.test(code));
   - text: <code>myArray</code> should equal <code>[1,2,3,4,5]</code>.
     testString: assert.deepEqual(myArray, [1,2,3,4,5]);
 
@@ -79,10 +79,6 @@ if (typeof myArray !== "undefined"){(function(){return myArray;})();}
 
 
 ```js
-var ourArray = [];
-for (var i = 0; i < 5; i++) {
-  ourArray.push(i);
-}
 var myArray = [];
 for (var i = 1; i < 6; i++) {
   myArray.push(i);

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/use-bracket-notation-to-find-the-nth-to-last-character-in-a-string.english.md

@@ -74,9 +74,6 @@ var secondToLastLetterOfLastName = lastName; // Change this line
 
 
 ```js
-var firstName = "Ada";
-var thirdToLastLetterOfFirstName = firstName[firstName.length - 3];
-
 var lastName = "Lovelace";
 var secondToLastLetterOfLastName = lastName[lastName.length - 2];
 ```