javascript中的类,继承,构造函数详解

    class A {
        constructor(name){
            this.name = name
        }
        getName(){
            return this.name
        }
    }
    var newA = new A("A")
    console.log(newA.getName())  // A

    class A {
        constructor(name){
            this.name = name
        }
        getName(){
            return this.name
        }
    }
    var newA = new A("A")
    console.log(newA.getName())  // A

console.log(newA.__proto__ === A.prototype)  // true

    console.log(A.prototype.constructor) // Class A

function Type() { };

var	types = [
	new Array,
    [],
	new Boolean,
    true,        // remains unchanged
	new Date,
	new Error,
	new Function,
	function(){},
	Math,
	new Number,
	1,           // remains unchanged
	new Object,
	{},
	new RegExp,
	/(?:)/,
	new String,
	"test"       // remains unchanged
];

for(var i = 0; i < types.length; i++) {
	types[i].constructor = Type;
	types[i] = [ types[i].constructor, types[i] instanceof Type, types[i].toString() ];
};

console.log( types.join("\n") );

    class Father{
        constructor(name){
            this.name = name
        }
    }
    class Son extends Father{
        constructor(name,sname){
            super(name)
            this.sname = sname
        }
        getSon(){
            return this
        }
    }
    var newSon = new Son("f","s")
    console.log(newSon.getSon())  // Son {name: 'f', sname: 's'}

    // 寄生组合继承
    function Sub(name){
        // 优先执行this绑定，以免覆盖子类的构造的值
        // 这里还有一个作用是拷贝了父类属性，避免所有子类共享引用属性！！！！
        Person.call(this)
        this.name = name || 's'
    }
    // 复制一份父类的原型，避免修改原型影响其他实例
    var fn = function(){}
    fn.prototype = Person.prototype
    Sub.prototype = new fn()
    var sub = new Sub('sub')
    sub.showName() 
    // user extend.html:19
    // my name is sub extend.html:21