Destructuring

Extract values from objects and arrays with concise syntax.

Object Destructuring

const user = {
  name: 'Alice',
  age: 30,
  email: 'alice@example.com'
};

// Basic destructuring
const {name, age} = user;
console.log(name);  // Alice

// Rename variables
const {name: userName, age: userAge} = user;
console.log(userName);  // Alice

// Default values
const {role = 'user'} = user;
console.log(role);  // user

// Nested destructuring
const config = {
  server: {
    host: 'localhost',
    port: 3000
  }
};
const {server: {host, port}} = config;
console.log(host);  // localhost

Array Destructuring

const colors = ['red', 'green', 'blue', 'yellow'];

// Basic destructuring
const [first, second] = colors;
console.log(first);  // red

// Skip elements
const [, , third] = colors;
console.log(third);  // blue

// Rest operator
const [primary, ...others] = colors;
console.log(others);  // ['green', 'blue', 'yellow']

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

Function Parameters

function printUser({name, age}) {
  console.log(`${name} is ${age} years old`);
}

printUser({name: 'Bob', age: 25});  // Bob is 25 years old