JSFiddle - React, Tailwind, and code Playground

JavaScript

BASE = function () {
    var that = {};
    var number = 10;
    
    that.showNumber = function(){
        that.alertNumber();
    }

    that.alertNumber = function () {
        alert(number);
    };    
    return that;
};

CHILD = function () {
    var that = Object.create(BASE());
    var secondNumber = 20;

    // Override base function
    that.alertNumber = function () {
        alert(secondNumber);
    };
    return that;
};

var ch = CHILD();
ch.showNumber();