js类class继承实现_js类class继承全面讲解

function Parent(name) {
  this.name = name;
}

Parent.prototype.sayHello = function() {
  console.log("Hello, I'm " + this.name);
};

function Child(name, age) {
  Parent.call(this, name); // 借用构造函数，继承父类的实例属性
  this.age = age;
}

// 核心：将子类的原型指向父类的实例
Child.prototype = Object.create(Parent.prototype);
Child.prototype.constructor = Child; // 修正 constructor 指向

Child.prototype.sayAge = function() {
  console.log("I'm " + this.age + " years old.");
};

const child = new Child("Alice", 10);
child.sayHello(); // 输出: Hello, I'm Alice
child.sayAge();   // 输出: I'm 10 years old.

class Parent {
  constructor(name) {
    this.name = name;
  }

  sayHello() {
    console.log("Hello, I'm " + this.name);
  }
}

class Child extends Parent {
  constructor(name, age) {
    super(name); // 调用父类的构造函数
    this.age = age;
  }

  sayAge() {
    console.log("I'm " + this.age + " years old.");
  }
}

const child = new Child("Bob", 12);
child.sayHello(); // 输出: Hello, I'm Bob
child.sayAge();   // 输出: I'm 12 years old.

class Parent {
  constructor(name) {
    this.name = name;
  }

  sayHello() {
    console.log("Hello, I'm " + this.name);
  }
}

class Child extends Parent {
  constructor(name, age) {
    super(name); // 调用父类的构造函数
    this.age = age;
  }

  sayHello() {
    super.sayHello(); // 调用父类的 sayHello 方法
    console.log("I'm also a child.");
  }
}

const child = new Child("Charlie", 8);
child.sayHello();
// 输出:
// Hello, I'm Charlie
// I'm also a child.

function mixin(target, ...sources) {
  for (const source of sources) {
    for (const key of Object.getOwnPropertyNames(source.prototype)) {
      if (key !== 'constructor') {
        Object.defineProperty(target.prototype, key, Object.getOwnPropertyDescriptor(source.prototype, key));
      }
    }
  }
}

class CanFly {
  fly() {
    console.log("I can fly!");
  }
}

class CanSwim {
  swim() {
    console.log("I can swim!");
  }
}

class Duck {
  constructor(name) {
    this.name = name;
  }
}

mixin(Duck, CanFly, CanSwim);

const duck = new Duck("Donald");
duck.fly();  // 输出: I can fly!
duck.swim(); // 输出: I can swim!

class Flyable {
  constructor(obj) {
    this.obj = obj;
  }

  fly() {
    console.log(this.obj.name + " can fly!");
  }
}

class Swimmable {
  constructor(obj) {
    this.obj = obj;
  }

  swim() {
    console.log(this.obj.name + " can swim!");
  }
}

class Duck {
  constructor(name) {
    this.name = name;
    this.flyable = new Flyable(this);
    this.swimmable = new Swimmable(this);
  }

  fly() {
    this.flyable.fly();
  }

  swim() {
    this.swimmable.swim();
  }
}

const duck = new Duck("Daisy");
duck.fly();  // 输出: Daisy can fly!
duck.swim(); // 输出: Daisy can swim!