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>
107 lines
2.4 KiB
Markdown
107 lines
2.4 KiB
Markdown
---
|
|
id: 587d7b89367417b2b2512b4a
|
|
title: Use Destructuring Assignment to Assign Variables from Nested Objects
|
|
challengeType: 1
|
|
forumTopicId: 301214
|
|
dashedName: use-destructuring-assignment-to-assign-variables-from-nested-objects
|
|
---
|
|
|
|
# --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;
|
|
```
|
|
|
|
# --instructions--
|
|
|
|
Replace the two assignments with an equivalent destructuring assignment. It should still assign the variables `lowToday` and `highToday` the values of `today.low` and `today.high` from the `LOCAL_FORECAST` object.
|
|
|
|
# --hints--
|
|
|
|
You should remove the ES5 assignment syntax.
|
|
|
|
```js
|
|
assert(
|
|
!code.match(/lowToday = LOCAL_FORECAST\.today\.low/g) &&
|
|
!code.match(/highToday = LOCAL_FORECAST\.today.high/g)
|
|
);
|
|
```
|
|
|
|
You should use destructuring to create the `lowToday` variable.
|
|
|
|
```js
|
|
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
|
|
)
|
|
);
|
|
```
|
|
|
|
You should use destructuring to create the `highToday` variable.
|
|
|
|
```js
|
|
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
|
|
)
|
|
);
|
|
```
|
|
|
|
`lowToday` should be equal to `64` and `highToday` should be equal to `77`.
|
|
|
|
```js
|
|
assert(lowToday === 64 && highToday === 77);
|
|
```
|
|
|
|
# --seed--
|
|
|
|
## --seed-contents--
|
|
|
|
```js
|
|
const LOCAL_FORECAST = {
|
|
yesterday: { low: 61, high: 75 },
|
|
today: { low: 64, high: 77 },
|
|
tomorrow: { low: 68, high: 80 }
|
|
};
|
|
|
|
// Only change code below this line
|
|
|
|
const lowToday = LOCAL_FORECAST.today.low;
|
|
const highToday = LOCAL_FORECAST.today.high;
|
|
|
|
// Only change code above this line
|
|
```
|
|
|
|
# --solutions--
|
|
|
|
```js
|
|
const LOCAL_FORECAST = {
|
|
yesterday: { low: 61, high: 75 },
|
|
today: { low: 64, high: 77 },
|
|
tomorrow: { low: 68, high: 80 }
|
|
};
|
|
|
|
const { today: { low: lowToday, high: highToday }} = LOCAL_FORECAST;
|
|
```
|