bd68b70f3d
* fix: remove isHidden flag from frontmatter * fix: add isUpcomingChange Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com> * feat: hide blocks not challenges Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com> Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com>
84 lines
1.9 KiB
Markdown
84 lines
1.9 KiB
Markdown
---
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id: 56bbb991ad1ed5201cd392cd
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title: Manipulate Arrays With shift()
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cRbVETW'
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forumTopicId: 18238
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---
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## Description
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<section id='description'>
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<code>pop()</code> always removes the last element of an array. What if you want to remove the first?
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That's where <code>.shift()</code> comes in. It works just like <code>.pop()</code>, except it removes the first element instead of the last.
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Example:
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```js
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var ourArray = ["Stimpson", "J", ["cat"]];
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var removedFromOurArray = ourArray.shift();
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// removedFromOurArray now equals "Stimpson" and ourArray now equals ["J", ["cat"]].
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```
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</section>
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## Instructions
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<section id='instructions'>
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Use the <code>.shift()</code> function to remove the first item from <code>myArray</code>, assigning the "shifted off" value to <code>removedFromMyArray</code>.
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>myArray</code> should now equal <code>[["dog", 3]]</code>.
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testString: assert((function(d){if(d[0][0] == 'dog' && d[0][1] === 3 && d[1] == undefined){return true;}else{return false;}})(myArray));
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- text: <code>removedFromMyArray</code> should contain <code>["John", 23]</code>.
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testString: assert((function(d){if(d[0] == 'John' && d[1] === 23 && typeof removedFromMyArray === 'object'){return true;}else{return false;}})(removedFromMyArray));
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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// Setup
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var myArray = [["John", 23], ["dog", 3]];
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// Only change code below this line
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var removedFromMyArray;
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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var myArray = [["John", 23], ["dog", 3]];
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// Only change code below this line
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var removedFromMyArray = myArray.shift();
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```
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</section>
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