javascript insert a new number into an array upon event code example

Example 1: javascript insert item into array

var colors=["red","blue"];
var index=1;

//insert "white" at index 1
colors.splice(index, 0, "white");   //colors =  ["red", "white", "blue"]

Example 2: javscript append item from array

let foo = ['oop','plop','copo'];
	foo.push("plop");