ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
68 lines
1.6 KiB
Markdown
68 lines
1.6 KiB
Markdown
---
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id: 587d7b89367417b2b2512b4b
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title: Use Destructuring Assignment to Assign Variables from Arrays
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challengeType: 1
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forumTopicId: 301213
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dashedName: use-destructuring-assignment-to-assign-variables-from-arrays
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---
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# --description--
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ES6 makes destructuring arrays as easy as destructuring objects.
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One key difference between the spread operator and array destructuring is that the spread operator unpacks all contents of an array into a comma-separated list. Consequently, you cannot pick or choose which elements you want to assign to variables.
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Destructuring an array lets us do exactly that:
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```js
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const [a, b] = [1, 2, 3, 4, 5, 6];
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console.log(a, b); // 1, 2
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```
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The variable `a` is assigned the first value of the array, and `b` is assigned the second value of the array. We can also access the value at any index in an array with destructuring by using commas to reach the desired index:
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```js
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const [a, b,,, c] = [1, 2, 3, 4, 5, 6];
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console.log(a, b, c); // 1, 2, 5
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```
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# --instructions--
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Use destructuring assignment to swap the values of `a` and `b` so that `a` receives the value stored in `b`, and `b` receives the value stored in `a`.
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# --hints--
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Value of `a` should be 6, after swapping.
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```js
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assert(a === 6);
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```
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Value of `b` should be 8, after swapping.
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```js
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assert(b === 8);
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```
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You should use array destructuring to swap a and b.
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```js
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assert(/\[\s*(\w)\s*,\s*(\w)\s*\]\s*=\s*\[\s*\2\s*,\s*\1\s*\]/g.test(code));
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```
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# --seed--
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## --seed-contents--
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```js
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let a = 8, b = 6;
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// Only change code below this line
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```
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# --solutions--
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```js
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let a = 8, b = 6;
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[a, b] = [b, a];
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```
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