destructuring assignment

The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.

Array destructuring

let a, b;
[a, b] = [1, 2];
console.log(a); // 1
console.log(b); // 2

Object destructuring

const user = {
    id: 42,
    is_verified: true
};
const {id, is_verified} = user;
console.log(id); // 42
console.log(is_verified); // true

Unpacking fields from objects passed as a function parameter

const user = {
  id: 42,
  displayName: 'jdoe',
  fullName: {
    firstName: 'John',
    lastName: 'Doe'
  }
};
function userId({id}) {
  return id;
}
function whois({displayName, fullName: {firstName: name}}) {
  return `${displayName} is ${name}`;
}
console.log(userId(user)); // 42
console.log(whois(user));  // "jdoe is John"

source: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment