一.类的创建及其方法和属性的调用
代码实例:
class Star { constructor(uname, age) {
//此时的this指向实例化对象 this.uname = uname, this.age = age } sing(song) { console.log(this.uname + song); } } var ldh = new Star('刘德华', 54); var zxy = new Star('张学友', 56); console.log(ldh); console.log(zxy); ldh.sing('冰雨')
注意事项:
- 通过class关键字创建类,类名首字母大写;
- 类里面的constructor函数,可以接受传递过来的参数,同时返回实例对象;
- constructor函数只要new生成实例是,就会自动调用这个函数;
- es6中没有变量的提升,必须先定义类,再实例化对象.
二.类的继承
(1)extends的继承
class Father { constructor() {} money() { console.log(100); } } class Son extends Father {} var son = new Son(); son.money();//100
class Father { constructor(x, y) { this.x = x; this.y = y } sum() { console.log(this.x + this.y); } } class Son extends Father { constructor(x, y) { //此时,super关键字必须放置this之前 super(x, y) this.x = x; this.y = y; } subtract() { console.log(this.x - this.y); }; } var son = new Son(11, 2); son.subtract();//9 son.sum();//13