javascript add element to array at index 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 append to array

var colors=["red","white"];
colors.push("blue");//append 'blue' to colors

Example 3: How to insert an item into an array at a specific index JavaScript

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join());
arr.splice(2, 0, "Lene");
console.log(arr.join());

Example 4: javascript add array to array at index

a1.splice(2, 0, ...a2);

Example 5: add item to array javascript

const arr1 = [1,2,3]
const newValue = 4
const newData = [...arr1, obj] // [1,2,3,4]

Example 6: 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