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

id, title, challengeType

id	title	challengeType
56bbb991ad1ed5201cd392cd	Manipulate Arrays With shift()	1

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.

Tests

tests:
  - text: <code>myArray</code> should now equal <code>[["dog", 3]]</code>.
    testString: assert((function(d){if(d[0][0] == 'dog' && d[0][1] === 3 && d[1] == undefined){return true;}else{return false;}})(myArray), '<code>myArray</code> should now equal <code>[["dog", 3]]</code>.');
  - text: <code>removedFromMyArray</code> should contain <code>["John", 23]</code>.
    testString: assert((function(d){if(d[0] == 'John' && d[1] === 23 && typeof removedFromMyArray === 'object'){return true;}else{return false;}})(removedFromMyArray), '<code>removedFromMyArray</code> should contain <code>["John", 23]</code>.');

Challenge Seed

// Example
var ourArray = ["Stimpson", "J", ["cat"]];
var 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;

After Test

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

Solution

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

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