js给class对象赋值

class Person {
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }

  getFullName() {
    return `${this.firstName} ${this.lastName}`;
  }
}

// 创建Person类的实例并赋值
const person1 = new Person('John', 'Doe');
console.log(person1.getFullName()); // 输出: John Doe

// 直接给实例属性赋值
person1.firstName = 'Jane';
console.log(person1.getFullName()); // 输出: Jane Doe

console.log(person1.age); // 输出: undefined

if ('age' in person1) {
  console.log(person1.age);
} else {
  console.log('Age is not defined');
}

class Person {
  constructor(firstName, lastName) {
    this._firstName = firstName;
    this._lastName = lastName;
  }

  get firstName() {
    return this._firstName;
  }

  set firstName(value) {
    if (typeof value === 'string') {
      this._firstName = value;
    } else {
      throw new Error('First name must be a string');
    }
  }

  // ...其他属性和方法
}