freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/manipulate-arrays-with-shift.md

id, title, challengeType, videoUrl, forumTopicId

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

--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 now equals "Stimpson" and ourArray now equals ["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();