101 lines
2.7 KiB
Markdown
101 lines
2.7 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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---
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## Description
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<section id='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 <code>name</code> and <code>age</code> variables will be created and assigned the values of their respective values from the <code>user</code> 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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</section>
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## Instructions
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<section id='instructions'>
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Replace the two assignments with an equivalent destructuring assignment. It should still assign the variables <code>today</code> and <code>tomorrow</code> the values of <code>today</code> and <code>tomorrow</code> from the <code>HIGH_TEMPERATURES</code> object.
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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: You should remove the ES5 assignment syntax.
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testString: assert(!code.match(/today = HIGH_TEMPERATURES\.today/g) && !code.match(/tomorrow = HIGH_TEMPERATURES\.tomorrow/g))
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- text: You should use destructuring to create the <code>today</code> variable.
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testString: assert(code.match(/(var|let|const)\s*{\s*(today[^}]*|[^,]*,\s*today)\s*}\s*=\s*HIGH_TEMPERATURES(;|\s+|\/\/)/g));
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- text: You should use destructuring to create the <code>tomorrow</code> variable.
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testString: assert(code.match(/(var|let|const)\s*{\s*(tomorrow[^}]*|[^,]*,\s*tomorrow)\s*}\s*=\s*HIGH_TEMPERATURES(;|\s+|\/\/)/g));
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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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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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// 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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// change code above this line
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console.log(yesterday) // should be not defined
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console.log(today); // should be 77
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console.log(tomorrow); // should be 80
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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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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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// change code below this line
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const { today, tomorrow } = HIGH_TEMPERATURES;
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// change code above this line
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console.log(yesterday) // should be not defined
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console.log(today); // should be 77
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console.log(tomorrow); // should be 80
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```
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</section>
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