102 lines
2.7 KiB
Markdown
102 lines
2.7 KiB
Markdown
---
|
|
id: 587d7b89367417b2b2512b4a
|
|
title: Use Destructuring Assignment to Assign Variables from Nested Objects
|
|
challengeType: 1
|
|
---
|
|
|
|
## Description
|
|
<section id='description'>
|
|
You can use the same principles from the previous two lessons to destructure values from nested objects.
|
|
|
|
Using an object similar to previous examples:
|
|
|
|
```js
|
|
const user = {
|
|
johnDoe: {
|
|
age: 34,
|
|
email: 'johnDoe@freeCodeCamp.com'
|
|
}
|
|
};
|
|
```
|
|
|
|
Here's how to extract the values of object properties and assign them to variables with the same name:
|
|
|
|
```js
|
|
const { johnDoe: { age, email }} = user;
|
|
```
|
|
|
|
And here's how you can assign an object properties' values to variables with different names:
|
|
|
|
```js
|
|
const { johnDoe: { age: userAge, email: userEmail }} = user;
|
|
```
|
|
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
Replace the two assignments with an equivalent destructuring assignment. It should still assign the variables <code>lowToday</code> and <code>highToday</code> the values of <code>today.low</code> and <code>today.high</code> from the <code>LOCAL_FORECAST</code> object.
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: You should remove the ES5 assignment syntax.
|
|
testString: assert(!code.match(/lowToday = LOCAL_FORECAST\.today\.low/g) && !code.match(/highToday = LOCAL_FORECAST\.today.high/g))
|
|
- text: You should use destructuring to create the <code>lowToday</code> variable.
|
|
testString: assert(code.match(/(var|const|let)\s*{\s*today\s*:\s*{\s*(low\s*:\s*lowToday[^}]*|[^,]*,\s*low\s*:\s*lowToday\s*)}\s*}\s*=\s*LOCAL_FORECAST(;|\s+|\/\/)/g));
|
|
- text: You should use destructuring to create the <code>highToday</code> variable.
|
|
testString: assert(code.match(/(var|const|let)\s*{\s*today\s*:\s*{\s*(high\s*:\s*highToday[^}]*|[^,]*,\s*high\s*:\s*highToday\s*)}\s*}\s*=\s*LOCAL_FORECAST(;|\s+|\/\/)/g));
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
const LOCAL_FORECAST = {
|
|
yesterday: { low: 61, high: 75 },
|
|
today: { low: 64, high: 77 },
|
|
tomorrow: { low: 68, high: 80 }
|
|
};
|
|
|
|
// change code below this line
|
|
|
|
const lowToday = LOCAL_FORECAST.today.low;
|
|
const highToday = LOCAL_FORECAST.today.high;
|
|
|
|
// change code above this line
|
|
|
|
console.log(lowToday); // should be 64
|
|
console.log(highToday); // should be 77
|
|
```
|
|
|
|
</div>
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
```js
|
|
const LOCAL_FORECAST = {
|
|
yesterday: { low: 61, high: 75 },
|
|
today: { low: 64, high: 77 },
|
|
tomorrow: { low: 68, high: 80 }
|
|
};
|
|
|
|
// change code below this line
|
|
|
|
const { today: { low: lowToday, high: highToday }} = LOCAL_FORECAST;
|
|
|
|
// change code above this line
|
|
|
|
console.log(highToday); // should be 77
|
|
console.log(highTomorrow); // should be 80
|
|
```
|
|
|
|
</section>
|