JavaScript 继承 封装 多态实现及原理详解

var parent = function(name,age){
 this.name = name;
 this.age = age;
}
 
parent.prototype.showProper = function(){
 console.log(this.name+":"+this.age);
}
 
var child = function(name,age){
 parent.call(this,name,age);
}
 
// inheritance
child.prototype = Object.create(parent.prototype);
// child.prototype = new parent();
child.prototype.constructor = child;
 
// rewrite function
child.prototype.showProper = function(){
 console.log('I am '+this.name+":"+this.age);
}

var obj = new child('wozien','22');
obj.showProper();

class a {
 add(){
 return 11
 }
 }
 class b extends a{
 
 }
 let c = new b()
 console.log(c.add()) // 111