deconstruct js code example

Example 1: javascript object destructuring

//simple example with object------------------------------
let obj = {name: 'Max', age: 22, address: 'Delhi'};
const {name, age} = obj;

console.log(name);
//expected output: "Max"

console.log(age);
//expected output: 22

console.log(address);
//expected output: Uncaught ReferenceError: address is not defined

// simple example with array-------------------------------
let a, b, rest;
[a, b] = [10, 20];

console.log(a);
// expected output: 10

console.log(b);
// expected output: 20

[a, b, ...rest] = [10, 20, 30, 40, 50];

console.log(rest);
// expected output: Array [30,40,50]

Example 2: object destructuring

const book = {
    title: 'Ego is the Enemy',
    author: 'Ryan Holiday',
    publisher: {
        name: 'Penguin',
        type: 'private'
    }
};

const {title: bookName =  'Ego', author, name: {publisher: { name }} = book, type: {publisher: { type }} = book } = book;

Example 3: javascript deconstruct object

const objA = {
 prop1: 'foo',
 prop2: {
   prop2a: 'bar',
   prop2b: 'baz',
 },
};

// Deconstruct nested props
const { prop1, prop2: { prop2a, prop2b } } = objA;

console.log(prop1);  // 'foo'
console.log(prop2a); // 'bar'
console.log(prop2b); // 'baz'

Example 4: array destructuring

//Without destructuring

const myArray = ["a", "b", "c"];

const x = myArray[0];
const y = myArray[1];

console.log(x, y); // "a" "b"

//With destructuring

const myArray = ["a", "b", "c"];

const [x, y] = myArray; // That's it !

console.log(x, y); // "a" "b"

Example 5: destructuring assignment

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

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

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

Example 6: object destructuring

let a, b, rest;
[a, b] = [10, 20];

console.log(a);
// expected output: 10

console.log(b);
// expected output: 20

[a, b, ...rest] = [10, 20, 30, 40, 50];

console.log(rest);
// expected output: Array [30,40,50]