65 lines
2.2 KiB
Markdown
65 lines
2.2 KiB
Markdown
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---
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id: 587d7da9367417b2b2512b66
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title: Combine Two Arrays Using the concat Method
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challengeType: 1
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---
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## Description
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<section id='description'>
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<code>Concatenation</code> means to join items end to end. JavaScript offers the <code>concat</code> method for both strings and arrays that work in the same way. For arrays, the method is called on one, then another array is provided as the argument to <code>concat</code>, which is added to the end of the first array. It returns a new array and does not mutate either of the original arrays. Here's an example:
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<blockquote>[1, 2, 3].concat([4, 5, 6]);<br>// Returns a new array [1, 2, 3, 4, 5, 6]</blockquote>
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</section>
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## Instructions
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<section id='instructions'>
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Use the <code>concat</code> method in the <code>nonMutatingConcat</code> function to concatenate <code>attach</code> to the end of <code>original</code>. The function should return the concatenated array.
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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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- text: Your code should use the <code>concat</code> method.
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testString: 'assert(code.match(/\.concat/g), "Your code should use the <code>concat</code> method.");'
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- text: The <code>first</code> array should not change.
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testString: 'assert(JSON.stringify(first) === JSON.stringify([1, 2, 3]), "The <code>first</code> array should not change.");'
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- text: The <code>second</code> array should not change.
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testString: 'assert(JSON.stringify(second) === JSON.stringify([4, 5]), "The <code>second</code> array should not change.");'
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- text: '<code>nonMutatingConcat([1, 2, 3], [4, 5])</code> should return <code>[1, 2, 3, 4, 5]</code>.'
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testString: 'assert(JSON.stringify(nonMutatingConcat([1, 2, 3], [4, 5])) === JSON.stringify([1, 2, 3, 4, 5]), "<code>nonMutatingConcat([1, 2, 3], [4, 5])</code> should return <code>[1, 2, 3, 4, 5]</code>.");'
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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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function nonMutatingConcat(original, attach) {
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// Add your code below this line
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// Add your code above this line
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}
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var first = [1, 2, 3];
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var second = [4, 5];
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nonMutatingConcat(first, second);
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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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// solution required
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```
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</section>
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