ES6 object-oriented basics

ES6 object-oriented:
1. The class keyword, the constructor and the class are separated
2. The method is directly added in the class

class User{
    
    
	constructor(name,pass){
    
    
		this.name=name;
		this.pass=pass;
	}

	showName(){
    
    
		alert(this.name);
	}
	showPass(){
    
    
		alert(this.pass);
	}
}

	var u1 = new User('blue','123456');

	u1.showName();
	u1.showPass();

inherit:

class User{
    
    
	constructor(name,pass){
    
    
		this.name=name;
		this.pass=pass;
	}

	showName(){
    
    
		alert(this.name);
	}
	showPass(){
    
    
		alert(this.pass);
	}
}

class VipUser extends User{
    
    
	constructor(name,pass,level){
    
    
		super(name,pass);
		this.level=level;
	}
	
	showLevel(){
    
    
		alert(this.level);
	}
}

	var v1 = new VipUser('blue','123456',3);

	v1.showName();
	v1.showPass();
	v1.showLevel();