js子类继承父类所有属性和方法

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

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

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

// 设置Child的原型为Parent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 am ' + this.age + ' years old.');
};

var child = new Child('Alice', 10);
child.sayHello(); // 输出: Hello, my name is Alice
child.sayAge();   // 输出: I am 10 years old.

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

  sayHello() {
    console.log(`Hello, my name is ${this.name}`);
  }
}

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

  sayAge() {
    console.log(`I am ${this.age} years old.`);
  }
}

const child = new Child('Alice', 10);
child.sayHello(); // 输出: Hello, my name is Alice
child.sayAge();   // 输出: I am 10 years old.