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>
109 lines
2.3 KiB
Markdown
109 lines
2.3 KiB
Markdown
---
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id: 5cfa550e84205a357704ccb6
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title: Use Destructuring Assignment to Extract Values from Objects
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challengeType: 1
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forumTopicId: 301216
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dashedName: use-destructuring-assignment-to-extract-values-from-objects
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---
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# --description--
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<dfn>Destructuring assignment</dfn> is special syntax introduced in ES6, for neatly assigning values taken directly from an object.
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Consider the following ES5 code:
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```js
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const user = { name: 'John Doe', age: 34 };
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const name = user.name; // name = 'John Doe'
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const age = user.age; // age = 34
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```
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Here's an equivalent assignment statement using the ES6 destructuring syntax:
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```js
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const { name, age } = user;
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// name = 'John Doe', age = 34
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```
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Here, the `name` and `age` variables will be created and assigned the values of their respective values from the `user` object. You can see how much cleaner this is.
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You can extract as many or few values from the object as you want.
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# --instructions--
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Replace the two assignments with an equivalent destructuring assignment. It should still assign the variables `today` and `tomorrow` the values of `today` and `tomorrow` from the `HIGH_TEMPERATURES` object.
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# --hints--
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You should remove the ES5 assignment syntax.
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```js
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assert(
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!__helpers
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.removeJSComments(code)
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.match(/today\s*=\s*HIGH_TEMPERATURES\.(today|tomorrow)/g)
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);
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```
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You should use destructuring to create the `today` variable.
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```js
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assert(
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__helpers
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.removeJSComments(code)
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.match(
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/(var|let|const)\s*{\s*(today[^}]*|[^,]*,\s*today)\s*}\s*=\s*HIGH_TEMPERATURES(;|\s+|\/\/)/g
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)
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);
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```
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You should use destructuring to create the `tomorrow` variable.
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```js
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assert(
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__helpers
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.removeJSComments(code)
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.match(
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/(var|let|const)\s*{\s*(tomorrow[^}]*|[^,]*,\s*tomorrow)\s*}\s*=\s*HIGH_TEMPERATURES(;|\s+|\/\/)/g
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)
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);
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```
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`today` should be equal to `77` and `tomorrow` should be equal to `80`.
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```js
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assert(today === 77 && tomorrow === 80);
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```
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# --seed--
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## --seed-contents--
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```js
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const HIGH_TEMPERATURES = {
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yesterday: 75,
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today: 77,
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tomorrow: 80
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};
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// Only change code below this line
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const today = HIGH_TEMPERATURES.today;
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const tomorrow = HIGH_TEMPERATURES.tomorrow;
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// Only change code above this line
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```
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# --solutions--
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```js
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const HIGH_TEMPERATURES = {
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yesterday: 75,
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today: 77,
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tomorrow: 80
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};
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const { today, tomorrow } = HIGH_TEMPERATURES;
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```
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