Javascript - insert an array inside another array

Question

What is the more efficient way to insert an array inside another array.

a1 = [1,2,3,4,5];
a2 = [21,22];

newArray - a1.insertAt(2,a2) -> [1,2, 21,22, 3,4         


        

Answer 1

var a1 = [1,2,3,4,5];
var a2 = [21,22];

function injectAt(d, a1, a2) {
    for(var i=a1.length-1; i>=d; i--) {
        a1[i + a2.length] = a1[i];
    }
    for(var i=0; i