es6 类

1. es5 类写法

    function People(name) {
      this.name = name;
    }
    People.prototype.getName = function () {
      return this.name;
    };
    var people = new People("strick");
    console.log(people.getName());

static a = 20;  // 等同于 Person.a = 20

继承 extends

class Student extends Person {}
继承的构造函数中，我们必须如上面的例子那么调用一次super方法，它表示构造函数的继承，与ES5中利用call/apply继承构造函数是一样的功能。

2. es6 类写法

    class People {
      constructor(name) {
        this.name = name;
      }
      getName() {
        return this.name;
      }
    }

3. es6 类相关概念

3.1 表达式

    var People = class Man {
      getSelf() {
        console.log(typeof Man); //"function"
        console.log(Man.name); //"Man"
        console.log(new Man().getAge()); //28
        return 'hello';
      }
      getAge() {
        return 28;
      }
    };
    var people = new People();
    console.log(people.getSelf());
    console.log(People.name); //"Man"
    console.log(Man.name); //Man未定义的错误

3.2 立即执行

    var people = new class {
      constructor(name) {  
        this.name = name;
      };
      getName() {
        return this.name;
      };      
    }("strick");
    console.log(people.getName()); //"strick"

3.3 自有属性

class People {
  constructor() {
    this.name = "strick";
  }
}

3.4 访问器属性

    class People {
      get prop() {
        return `getter:${this.name}`;
      }
      set prop(value) {
        this.name = value;
      }
    }
    var people = new People();
    people.prop = "strick";
    console.log(people.prop); // getter:strick

3.5 计算成员名

    var method = "getAge";
    class People {
      ["get" + "Name"]() {
        return "strick";
      }
      [method]() {
        return 28;
      }
    }
    var people = new People();
    console.log(people.getName()); //"strick"
    console.log(people.getAge()); //28

3.6 生成器

    class People {
      * getName() {
        yield "strick";
      }
    }
    var people = new People(),
      iterator = people.getName();
    console.log(iterator.next()); //{value: "strick", done: false}

3.7 静态方法

    class People {
      static getName() {
        return "strick";
      }
      getName2() {
        return "strick";
      }
    }
    var people=new People();
    console.log(people.getName2());