在javascript中正确组织类

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

  sayHello() {
    console.log(`Hello, my name is ${this.name} and I'm ${this.age} years old.`);
  }
}

const person = new Person("John", 25);
person.sayHello(); // 输出：Hello, my name is John and I'm 25 years old.

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

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

const student = new Student("Alice", 18, 12);
student.sayHello(); // 输出：Hello, my name is Alice and I'm 18 years old.
student.study(); // 输出：Alice is studying in grade 12.

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

console.log(MathUtils.add(2, 3)); // 输出：5