Break down and extract the fully organized variable using a single expression

Question

Break down and extract the fully organized variable using a single expression

Is it possible to destructure a variable while still having access to the structured variable within the same function call?

For instance, what can be used in place of ??? below to achieve the desired result (and what other changes might need to be made in the code)?

const foo = ({ a, b }) => {
  console.log(a) // 1
  console.log(b) // 2
  console.log(???) // { a: 1, b: 2 }
}
const x = { a: 1, b: 2 }
foo(x)

I aim for both understanding and concise code - I am looking to avoid using const { a, b } = params as the first line within foo() when the entire params object may need to be passed on.

javascript destructuring

Answer 1

Answer №1

If you're looking for a way to reference an object after destructuring its argument, it's not possible. Once the argument is destructured, you can only access some of its properties, not the full object itself.

However, if the object and properties you need are part of a larger object, you can still achieve what you want by referencing the property name alone to get the object into a variable first, then destructure it later. Here's an example:

const foo = ({ obj: { a, b }, obj }) => {
  console.log(a) // 1
  console.log(b) // 2
  console.log(obj) // { a: 1, b: 2 }
}
const obj = { a: 1, b: 2 }
foo({ obj })

Your original code could potentially work if the object had a property that referenced itself, although this is quite unconventional:

const foo = ({ a, b, obj }) => {
  console.log(a) // 1
  console.log(b) // 2
  console.log(obj) // { a: 1, b: 2 }
}
const x = { a: 1, b: 2 }
x.obj = x;
foo(x)

Answer 2

If you're looking for a way to reference an object after destructuring its argument, it's not possible. Once the argument is destructured, you can only access some of its properties, not the full object itself.

However, if the object and properties you need are part of a larger object, you can still achieve what you want by referencing the property name alone to get the object into a variable first, then destructure it later. Here's an example:

const foo = ({ obj: { a, b }, obj }) => {
  console.log(a) // 1
  console.log(b) // 2
  console.log(obj) // { a: 1, b: 2 }
}
const obj = { a: 1, b: 2 }
foo({ obj })

Your original code could potentially work if the object had a property that referenced itself, although this is quite unconventional:

const foo = ({ a, b, obj }) => {
  console.log(a) // 1
  console.log(b) // 2
  console.log(obj) // { a: 1, b: 2 }
}
const x = { a: 1, b: 2 }
x.obj = x;
foo(x)

Break down and extract the fully organized variable using a single expression

Answer №1

Similar questions

How to stop AngularJS onClick event from causing scroll to jump to top of

Setting up a Webpack configuration to compile modules within the node_modules directory

Tips for testing views in ember.js using unit tests

Is there a CSS rule that can alter the appearance of links once they have been clicked on a different webpage?

Tips for extracting Stripe response post payment using a client-side-only integration

Unexpectedly, the child component within the modal in React Native has been resetting to its default state

Preventing Past Dates from Being Selected in JQuery Date Picker

When querying by an enum field, the Mongoose .find() method may return an empty array

What is the correct way to utilize the WhatsApp API for sending messages?

Stop the reloading of the parent page when the exit button is pressed on the popup screen

migrating information from one screen to another

Jump to a specific section on a different page when the links are already equipped with anchors for smooth scrolling

Utilizing jQuery to execute functions from various files simultaneously with a single load statement

Caution: Potential Unresolved Promise Rejection Detected (ID: 21) - Error: Undefined is not a valid object when trying to evaluate 'res.json'

How can I iterate through a directory containing files and extract the exported JavaScript object from each one?

Navigating through nested arrays to access JSON objects

display upcoming schedule and time

Using a JavaScript script in my HTML alongside Vue.js is not possible

A skeleton framework lacking a data storage backend

Include the name of the uploaded attachment in the textarea before hitting the submit button