JSFiddle - React, Tailwind, and code Playground

by ponyspy

JavaScript

function setCharAt(str,index,chr) {
    if(index > str.length-1) return str;
    return str.substr(0,index) + chr + str.substr(index+1);
}

var str = 'ccc';

var res = setCharAt(str, 1, 'a');

alert(res)