Destructuring

const [ a, b, c ] = [1,2,3];
console.log(b) // 2

const [ d, , f ] = [4,5,6];
console.log(f); // 6

const { id, surname, name } = {age:26, name: 'Matthieu'};
console.log(name); // Only name is defined so: Matthieu

const { test='Default value'} = {};
console.log(test);
// Default value

const {address} = {address: {street: 'Here', city:'There'}};
console.log(address);
// Object {street: "Here", city: "There"}