how to merge several arrays in one array in javascript code example

Example 1: javascript array concat spread operator

const arr1 = [1,2,3]
const arr2 = [4,5,6]
const arr3 = [...arr1, ...arr2] //arr3 ==> [1,2,3,4,5,6]

Example 2: concatenate multiple arrays javascript

const array1 = ['a', 'b', 'c'];
const array2 = ['d', 'e', 'f'];
const array3 = [...array1, ...array2];

console.log(array3);
// expected output: Array ["a", "b", "c", "d", "e", "f"]