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Cleaner Code with JavaScript Destructuring

imjoshellis profile image Josh Ellis ・2 min read

Destructuring is a really useful way to get named variables out of an object in JavaScript and can make your code more readable.

Imagine we had a data object that looked like this:

const data = {
  color: 'red',
  cost: 25,
  name: 'balloon'
}
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Without destructuring, we could access the values like this:

// ...
console.log(`The cost of the ${data.color} ${data.name} is ${data.cost}`)
// => 'The cost is 25'
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Even with short variables, that's already starting to feel cluttered.

Basic destructuring would look like this:

// ...
const { cost } = data
console.log(`The cost is ${cost}`)
// => 'The cost is 25'
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...which is identical to this:

// ...
const cost = data.cost
console.log(`The cost is ${cost}`)
// => 'The cost is 25'
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The big win with destructuring is when you want to pull multiple values off an object:

// ...
const { color, cost, name } = data
console.log(`The cost of the ${color} ${name} is ${cost}`)
// => 'The cost of the red balloon is 25'
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...instead of this:

// ...
const color = data.color
const cost = data.cost
const name = data.name
console.log(`The cost of the ${color} ${name} is ${cost}`)
// => 'The cost of the red balloon is 25'
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What if you don't like the name of a key? You can just change it:

const data = {
  color: 'red',
  cost: 25,
  name: 'balloon'
}

const { color, cost, name: itemName } = data
console.log(`The cost of the ${color} ${itemName} is ${cost}`)
// => 'The cost of the red balloon is 25'
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What about nested objects? If you want to access the items from just one key, you can put the key on the right side of the equal sign:

const data = {
  user: {
    name: 'Josh',
    email: 'josh@imjoshellis.com'
  }
}

const { name, email } = data.user
console.log(`The email of ${name} is ${email}`)
// => 'The email of Josh is josh@imjoshellis.com'
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What if you want values from multiple levels? No problem:

const data = {
  user: {
    name: 'Josh',
    email: 'josh@imjoshellis.com'
    activity: {
      status: 'inactive',
      lastLoggedIn: 'yesterday'
    }
  }
}

const { name, activity: { status, lastLoggedIn }} = data.user
console.log(`${name} logged in ${lastLoggedIn} and is currently ${status}`)
// => 'Josh logged in yesterday and is currently inactive'
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What if the key doesn't have a value? You can set a default which will get assigned if the value of the key is undefined:

const data1 = {}
const { undefinedKey = "default value" } = data1
console.log(undefinedKey)
// => "default value"

const data2 = { definedKey: "provided value" }
const { definedKey = "default value" } = data2
console.log(definedKey)
// => "provided value"
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This was a quick intro into how destructuring works in JavaScript. I hope you were able to learn something!

This article (not written by me) goes into more depth if you're looking for even more examples and explanations: https://dmitripavlutin.com/javascript-object-destructuring/#2-extracting-a-property

Discussion

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joshanaba profile image
Josh Anaba

I learnt object destructuring earlier but was unable to wrap my head around it ,not up till now, this was super helpful, goodbye to cluttered code.

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imjoshellis profile image
Josh Ellis Author

Awesome! I'm glad it was helpful!

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israel1116 profile image
israel1116

Awesome explication.

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gbenga profile image
Gbenga Ojo-Aromokudu

I've been avoiding destructuring for a while despite knowing it exists, but this just convinced me to start using it 🔥

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imjoshellis profile image
Josh Ellis Author

Glad to hear it -- Once you start using it, it's a lot simpler and more useful than you expect!