js 实现类构造

// 定义一个普通的类
class Person {
  constructor(name, age) {
    this.name = name;
    this.age = age;
  }

  sayHello() {
    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.sayHello(); // 输出: Hello, my name is Alice and I am 30 years old.

// 定义一个继承自Person的类
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 in grade ${this.grade}.`);
  }
}

// 创建Student类的实例
const student1 = new Student('Bob', 20, 'A');
student1.sayHello(); // 输出: Hello, my name is Bob and I am 20 years old.
student1.study(); // 输出: Bob is studying in grade A.

class MathUtils {
  static add(a, b) {
    return a + b;
  }
}

console.log(MathUtils.add(5, 3)); // 输出: 8