Question

正确的做法

➖➖➖➖➖➖➖➖➖类➖➖➖➖➖➖➖➖➖
class Animal {
  constructor(name) {
    this.name = name;
  }
  sayHi() {
    return `My name is ${this.name}`;
  }
}

let a = new Animal('Jack');
console.log(a.sayHi()); // My name is Jack
➖➖➖➖➖➖➖➖➖继承➖➖➖➖➖➖➖➖➖
class Cat extends Animal {
  constructor(name) {
    super(name); // 调用父类的 constructor(name)
    console.log(this.name);
  }
  sayHi() {
    return 'Meow, ' + super.sayHi(); // 调用父类的 sayHi()
  }
}

let c = new Cat('Tom'); // Tom
console.log(c.sayHi()); // Meow, My name is Tom
➖➖➖➖➖➖➖➖➖存储器➖➖➖➖➖➖➖➖➖
class Animal {
  constructor(name) {
    this.name = name;
  }
  get name() {
    return 'Jack';
  }
  set name(value) {
    console.log('setter: ' + value);
    this.name = value;
  }
}

let a = new Animal('Kitty'); // setter: Kitty
a.name = 'Tom'; // setter: Tom
console.log(a.name); // Jack
➖➖➖➖➖➖➖➖➖静态方法➖➖➖➖➖➖➖➖➖
class Animal {
  static isAnimal(a) {
    return a instanceof Animal;
  }
}

let a = new Animal('Jack');
Animal.isAnimal(a); // true
// 只能通过类名调用
a.isAnimal(a); // TypeError: a.isAnimal is not a function ❌
➖➖➖➖➖➖➖➖➖抽象类➖➖➖➖➖➖➖➖➖
// 只能被继承，不能被实例化
abstract class Animal {
  eat(){
  console.log('eat')
  }
  abstract sleep(): void
}
// 子类必须实现抽象类的抽象方法
class Dog extends Animal {
  constructor(name: string) {
    super()
    this.name = name
  }
  name: string;
  run() {}
  sleep() {
    console.log('dog sleep')
  }
}

let dog = new Dog('wang')
dog.eat()

11.1 类与接口的关系

interface Human {
  name: string;
  eat(): void;
}

// 实现接口中声明的属性
class Person implements Human {
  constructor(name: string) {
    this.name = name
  }
  name: string;
  eat() {}
}

// 接口可以像类一样实现继承
interface Man extends Human {
  run(): voild
}
interface Child {
  cry(): voild
}
interface Boy extends Man,Child {}

// 添加被继承过来的属性
let body: Boy = {
  name: 'xx',
  run() {},
  eat() {},
  cry() {}
}