JavaScript - Insert Character at a Given Position in a String

These are the following approaches to insert a character at a given position:

1. Using String Concatenation with Slicing

Split the string into two parts—before and after the position—and concatenate the character in between.

let str = "Hello GFG";
let ch = "!";
let idx = 5;

let res = str.slice(0, idx) + ch + str.slice(idx);
console.log(res); 

Hello! GFG

2. Using Template Literals

Using template literals, we can easily insert a character at a specified position in a string by breaking the string into two parts and injecting the new character between them.

let str = "Hello GFG";
let ch = "!";
let idx = 5;

let res = `${str.slice(0, idx)}${ch}${str.slice(idx)}`;
console.log(res); 

Hello! GFG

3. Using Arrays for Insertion

Convert the string into an array, insert the character at the desired position using array manipulation, and then join the array back into a string.

let str = "Hello GFG";
let ch = "!";
let idx = 5;

let arr = str.split(""); 
arr.splice(idx, 0, ch); 
let res = arr.join(""); 
console.log(res); 

Hello! GFG