javascritp push from left code example
Example 1: javascript add new array element to start of array
var colors = ["white","blue"];
colors.unshift("red"); //add red to beginning of colors
// colors = ["red","white","blue"]
Example 2: prepend to js array
var a = [1, 2, 3, 4];
a.unshift(0);
a; // => [0, 1, 2, 3, 4]