JSFiddle - React, Tailwind, and code Playground

by HemalathaThanigaivel

JavaScript

var str = '12345678';
var output = '';
for(var i = 0; i < str.length; i++) {
  output += str.charAt(i);
  if(i % 2 == 1 && i > 0) {
    output += ':';
  }
}
console.log(output.substring(0, output.length - 1));

console.log( str.replace(/(..?)/g, '$1:').slice(0,-1))