Babel is a Javascript transpiler which converts ES6 Javascript into plain vanilla Javascript ES5 which is understood by all browsers.
Here is a sample code in ES6
class Employee {} var narendra = new Person
The above code in ES5 look like below
"use strict"; function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } } var Employee = function Employee() { _classCallCheck(this, Employee); }; var narendra = new Person();