add array to array javascript

 // SPREAD OPERATOR
 const list1 = ["pepe", "luis", "rua"];
 const list2 = ["rojo", "verde", "azul"];
 const newList = [...list1, ...list2];
 // ["pepe", "luis", "rua", "rojo", "verde", "azul"]let chocholates = ['Mars', 'BarOne', 'Tex'];
let chips = ['Doritos', 'Lays', 'Simba'];
let sweets = ['JellyTots'];

let snacks = [];
snacks.concat(chocholates);
// snacks will now be ['Mars', 'BarOne', 'Tex']
// Similarly if we left the snacks array empty and used the following
snacks.concat(chocolates, chips, sweets);
//This would return the snacks array with all other arrays combined together
// ['Mars', 'BarOne', 'Tex', 'Doritos', 'Lays', 'Simba', 'JellyTots']
var list = ["foo", "bar"];


list.push("baz");


["foo", "bar", "baz"] // result

Array.prototype.insert = function ( index, item ) {
    this.splice( index, 0, item );
};var colors= ["red","blue"];
	colors.push("yellow"); //["red","blue","yellow"]var arrayA = [1, 2];
var arrayB = [3, 4];
var newArray = arrayA.concat(arrayB);