add element to array index javascript 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: javascript add array to array at index
a1.splice(2, 0, ...a2);
Example 3: add new element by index js
const arr = [ 1, 2, 3, 4 ];
arr[5] = 'Hello, world!';
console.log(arr); // [ 1, 2, 3, 4, <1 empty item>, 'Hello, world!' ]
console.log(arr.length); // 6