freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/es6/use-destructuring-assignment-to-assign-variables-from-objects.md
Oliver Eyton-Williams ee1e8abd87
feat(curriculum): restore seed + solution to Chinese (#40683)
* 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

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* refactor: remove unused challenge property 'name'

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Signed-off-by: nhcarrigan <nhcarrigan@gmail.com>

Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
2021-01-12 19:31:00 -07:00

2.2 KiB

id, title, challengeType, forumTopicId, dashedName
id title challengeType forumTopicId dashedName
587d7b89367417b2b2512b49 Use Destructuring Assignment to Assign Variables from Objects 1 301215 use-destructuring-assignment-to-assign-variables-from-objects

--description--

Destructuring allows you to assign a new variable name when extracting values. You can do this by putting the new name after a colon when assigning the value.

Using the same object from the last example:

const user = { name: 'John Doe', age: 34 };

Here's how you can give new variable names in the assignment:

const { name: userName, age: userAge } = user;
// userName = 'John Doe', userAge = 34

You may read it as "get the value of user.name and assign it to a new variable named userName" and so on.

--instructions--

Replace the two assignments with an equivalent destructuring assignment. It should still assign the variables highToday and highTomorrow the values of today and tomorrow from the HIGH_TEMPERATURES object.

--hints--

You should remove the ES5 assignment syntax.

assert(
  !code.match(/highToday = HIGH_TEMPERATURES\.today/g) &&
    !code.match(/highTomorrow = HIGH_TEMPERATURES\.tomorrow/g)
);

You should use destructuring to create the highToday variable.

assert(
  code.match(
    /(var|const|let)\s*{\s*(today\s*:\s*highToday[^}]*|[^,]*,\s*today\s*:\s*highToday\s*)}\s*=\s*HIGH_TEMPERATURES(;|\s+|\/\/)/g
  )
);

You should use destructuring to create the highTomorrow variable.

assert(
  code.match(
    /(var|const|let)\s*{\s*(tomorrow\s*:\s*highTomorrow[^}]*|[^,]*,\s*tomorrow\s*:\s*highTomorrow\s*)}\s*=\s*HIGH_TEMPERATURES(;|\s+|\/\/)/g
  )
);

highToday should be equal to 77 and highTomorrow should be equal to 80.

assert(highToday === 77 && highTomorrow === 80);

--seed--

--seed-contents--

const HIGH_TEMPERATURES = {
  yesterday: 75,
  today: 77,
  tomorrow: 80
};

// Only change code below this line
  
const highToday = HIGH_TEMPERATURES.today;
const highTomorrow = HIGH_TEMPERATURES.tomorrow; 

// Only change code above this line

--solutions--

const HIGH_TEMPERATURES = {
  yesterday: 75,
  today: 77,
  tomorrow: 80
};

const { today: highToday, tomorrow: highTomorrow } = HIGH_TEMPERATURES;