JSFiddle - React, Tailwind, and code Playground

JavaScript

var Base = function(x){
            this.x = x;
            this.propInSuper = 'hello im propInSuper';
        }

        Base.prototype = {
            getX : function(){
                console.log(this.x);
            }
        }

        var Child = function(x){
            Base.call(this, x);
        }

        Child.prototype = Object.create(Base.prototype);

        //@override
        Child.prototype.getX = function(){
            console.log(this.x * 2);
        }

        var child = new Child(5);
        child.getX(); // 10

        console.log('propInSuper: ' + child.propInSuper);