js 对象定义类

class Person {
  // 属性
  constructor(name, age) {
    this.name = name;
    this.age = age;
  }

  // 方法
  greet() {
    console.log(`Hello, my name is ${this.name} and I am ${this.age} years old.`);
  }
}

// 创建Person类的实例
const person1 = new Person('Alice', 30);
person1.greet(); // 输出: Hello, my name is Alice and I am 30 years old.

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

  study() {
    console.log(`${this.name} is studying.`);
  }
}

const student1 = new Student('Bob', 20, 'Grade 3');
student1.greet(); // 输出: Hello, my name is Bob and I am 20 years old.
student1.study(); // 输出: Bob is studying.

class Teacher extends Person {
  constructor(name, age, subject) {
    super(name, age);
    this.subject = subject;
  }

  teach() {
    super.greet(); // 调用父类的greet方法
    console.log(`${this.name} is teaching ${this.subject}.`);
  }
}

const teacher1 = new Teacher('Charlie', 40, 'Math');
teacher1.teach();
// 输出:
// Hello, my name is Charlie and I am 40 years old.
// Charlie is teaching Math.