一、继承

1. ES6的继承

// es6继承
  class Animal {
    //构造函数，里面写上对象的属性
    constructor(props) {
      this.name = props.name || 'Unknown';
    }
    //方法写在后面
    eat() {//父类共有的方法
      console.log(this.name + " will eat pests.");
    }
  }

  //class继承
  class Bird extends Animal {
    //构造函数
    constructor(props,myAttribute) {//props是继承过来的属性，myAttribute是自己的属性
      //调用实现父类的构造函数
      super(props)//相当于获得父类的this指向
      this.type = props.type || "Unknown";//父类的属性，也可写在父类中
      this.attr = myAttribute;//自己的私有属性
    }

    fly() {//自己私有的方法
      console.log(this.name + " are friendly to people.");
    }
    myattr() {//自己私有的方法
      console.log(this.type+'---'+this.attr);
    }
  }

//通过new实例化
  var myBird = new Bird({
    name: '小燕子',
    type: 'Egg animal'//卵生动物
  },'Bird class')
  myBird.eat()
  myBird.fly()
  myBird.myattr()

2. es5实现

重点代码
Animal.call(this,props)
继承父类属性Animal.call(this, name, type))
和
Bird.prototype = Object.create(Animal.prototype)
Bird.prototype.constructor = Bird

function Animal(props) {
    this.name = props.name || 'unknow'
  this.type = props.type || 'unknow'
}

Animal.prototype.eat = function () {
    console.log(this.name + 'will eat pests')
}

function Bird(props, myAttributes) {
    Animal.call(this,props)

    this.attr = myAttributes
}

Bird.prototype = Object.create(Animal.prototype)
Bird.prototype.constructor = Bird
Bird.prototype.fly = function () {
    console.log(this.name + 'are friendly to people')
}
Bird.prototype.myattr = function () {
    console.log(this.type + '---' + this.attr)
}
var myBird = new Bird({
    name: '小燕子',
    type: 'Egg animal'//卵生动物
}, 'Bird class')
myBird.eat()
myBird.fly()
myBird.myattr()