Using the Spread operator (...) you can quickly merge multiple Objects or Arrays together.

const user = {
	name: 'Ajay Karwal',
	twitter: '@ajaykarwal'
};

const appearance = {
	eyes: 'Brown',
	hair: 'Black',
	glasses: true
};

const profile = { ...user, ...appearance };

console.log(profile);

The result is a single merged Object

{
  eyes: "Brown",
  glasses: true,
  hair: "Black",
  name: "Ajay Karwal",
  twitter: "@ajaykarwal"
}

The same can be applied to Arrays.

const fruit = ['apples', 'bananas', 'strawberries'];

const veg = ['potatoes', 'spinach', 'cauliflower'];

const lunch = [...fruit, ...veg];

console.log(lunch);

// ["apples", "bananas", "strawberries", "potatoes", "spinach", "cauliflower"]

You can even merge Objects and Arrays, though the results might not be what you’re expecting.