js 引用父对象

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

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

function Child() {
    Parent.call(this); // 调用父类构造函数
    this.name = 'Child';
}

// 设置子类的原型为父类的实例，实现继承
Child.prototype = Object.create(Parent.prototype);
Child.prototype.constructor = Child; // 修复构造函数指向

var child = new Child();
child.sayHello(); // 输出: Hello, I am Child

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

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

class Child extends Parent {
    constructor() {
        super(); // 调用父类构造函数
        this.name = 'Child';
    }
}

const child = new Child();
child.sayHello(); // 输出: Hello, I am Child

class Child extends Parent {
    sayHello() {
        super.sayHello(); // 调用父类的sayHello方法
        console.log('And I am a child.');
    }
}

const child = new Child();
child.sayHello(); 
// 输出:
// Hello, I am Child
// And I am a child.

class Child extends Parent {
    constructor() {
        super(); // 必须先调用super()
        // 其他初始化代码
    }
}