freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/es6/use-destructuring-assignment-to-extract-values-from-objects.english.md

id, title, challengeType, forumTopicId

id	title	challengeType	forumTopicId
5cfa550e84205a357704ccb6	Use Destructuring Assignment to Extract Values from Objects	1	301216

Description

Destructuring assignment is special syntax introduced in ES6, for neatly assigning values taken directly from an object.

Consider the following ES5 code:

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

const name = user.name; // name = 'John Doe'
const age = user.age; // age = 34

Here's an equivalent assignment statement using the ES6 destructuring syntax:

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

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.

You can extract as many or few values from the object as you want.

Instructions

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.

Tests

tests:
  - text: You should remove the ES5 assignment syntax.
    testString: assert(!removeJSComments(code).match(/today\s*=\s*HIGH_TEMPERATURES\.(today|tomorrow)/g))
  - text: You should use destructuring to create the <code>today</code> variable.
    testString: assert(removeJSComments(code).match(/(var|let|const)\s*{\s*(today[^}]*|[^,]*,\s*today)\s*}\s*=\s*HIGH_TEMPERATURES(;|\s+|\/\/)/g));
  - text: You should use destructuring to create the <code>tomorrow</code> variable.
    testString: assert(removeJSComments(code).match(/(var|let|const)\s*{\s*(tomorrow[^}]*|[^,]*,\s*tomorrow)\s*}\s*=\s*HIGH_TEMPERATURES(;|\s+|\/\/)/g));
  - text: <code>today</code> should be equal to <code>77</code> and <code>tomorrow</code> should be equal to <code>80</code>.
    testString: assert(today === 77 && tomorrow === 80);

Challenge Seed

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

// Only change code below this line

const today = HIGH_TEMPERATURES.today;
const tomorrow = HIGH_TEMPERATURES.tomorrow;

// Only change code above this line

After Test

const removeJSComments = str => str.replace(/\/\*[\s\S]*?\*\/|\/\/.*$/gm, '');

Solution

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

const { today, tomorrow } = HIGH_TEMPERATURES;