freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-an.../basic-javascript/manipulate-arrays-with-shif...

1.8 KiB

id title challengeType videoUrl forumTopicId dashedName
56bbb991ad1ed5201cd392cd Manipulate Arrays With shift() 1 https://scrimba.com/c/cRbVETW 18238 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.

Example:

var ourArray = ["Stimpson", "J", ["cat"]];
var removedFromOurArray = ourArray.shift();

removedFromOurArray would have a value of the string Stimpson, and ourArray would have ["J", ["cat"]].

--instructions--

Use the .shift() function to remove the first item from myArray, assigning the "shifted off" value to removedFromMyArray.

--hints--

myArray should now equal [["dog", 3]].

assert(
  (function (d) {
    if (d[0][0] == 'dog' && d[0][1] === 3 && d[1] == undefined) {
      return true;
    } else {
      return false;
    }
  })(myArray)
);

removedFromMyArray should contain ["John", 23].

assert(
  (function (d) {
    if (
      d[0] == 'John' &&
      d[1] === 23 &&
      typeof removedFromMyArray === 'object'
    ) {
      return true;
    } else {
      return false;
    }
  })(removedFromMyArray)
);

--seed--

--after-user-code--

(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);

--seed-contents--

// Setup
var myArray = [["John", 23], ["dog", 3]];

// Only change code below this line
var removedFromMyArray;

--solutions--

var myArray = [["John", 23], ["dog", 3]];

// Only change code below this line
var removedFromMyArray = myArray.shift();