js merge array in array code example

Example 1: concat array javascript

const letters = ['a', 'b', 'c'];
const numbers = [1, 2, 3];

const newArray = letters.concat(numbers);
// newArrat is ['a', 'b', 'c', 1, 2, 3]

Example 2: js join two arrays

[1,2,3].concat([4,5,6])
// [1,2,3,4,5,6]