bfa5c26288
* Use dfn tags * remove misused <dfn> tags * Revert "remove misused <dfn> tags" This reverts commit b24968a96810f618d831410ac90a0bc452ebde50. * Update curriculum/challenges/english/01-responsive-web-design/basic-html-and-html5/fill-in-the-blank-with-placeholder-text.english.md Co-Authored-By: Randell Dawson <5313213+RandellDawson@users.noreply.github.com> * Make "array" lowercase Co-Authored-By: Randell Dawson <5313213+RandellDawson@users.noreply.github.com> * Fix dfn usage * Address last dfn tags
80 lines
2.1 KiB
Markdown
80 lines
2.1 KiB
Markdown
---
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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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forumTopicId: 301229
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---
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## Description
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<section id='description'>
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<dfn>Concatenation</dfn> 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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```js
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[1, 2, 3].concat([4, 5, 6]);
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// Returns a new array [1, 2, 3, 4, 5, 6]
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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>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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tests:
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- text: Your code should use the <code>concat</code> method.
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testString: assert(code.match(/\.concat/g));
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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]));
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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]));
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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]));
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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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function nonMutatingConcat(original, attach) {
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// Add your code below this line
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return original.concat(attach);
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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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</section>
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