JSFiddle - React, Tailwind, and code Playground

JavaScript

function Dog(_dogName){
    var that = this;
    
    var dogname = _dogName || "dog" ;//default setting
  
    that.getName = function(){
       return dogname;
    };
    
    that.setName = function(newName){
         dogname = newName;
    };

};
//use getName to access private member
Dog.prototype.getName = function(){
    return  dogname;
};
    
var myDog = new Dog();
console.log("mydog:" + myDog.getName());

var tomDog = new Dog("tom");
console.log("tomDog:" + tomDog.getName());
tomDog.setName("mary");
console.log("tomDog2:" + tomDog.getName());