javascript copy element from array and push to another code example

Example 1: javascript copy array

var oldColors=["red","green","blue"];
var newColors = oldColors.slice(); //make a clone/copy of oldColors

Example 2: javascript push all elements of array to another array

var arrayA = [1, 2];
var arrayB = [3, 4];
var newArray = arrayA.concat(arrayB);