Question

我想弄清楚为什么我不能调用我在课堂上设置的方法。我有一个es6课程

class school {
  constructor(size = '10', subjects = {
    math: 'green',
    physics: 'green',
    language: 'orange',
    history: null
  }) {
    this.size = size;
    this.subjects = subjects;
    this.classCode = null;
  }

  changeSubject(study) {
    this.classCode = this.subjects[study];
    if (study === 'math') {
      this.size += 1;
    }
  }
}

class room extends school {
  constructor(roomQty = 15, size, subjects) {
    super(size, subjects);
    this.roomQty = roomQty;
  }

  changeStudy(study) {
    super.changeStudy(study);
    if (study === 'math') {
      this.roomQty += 1;
    }
  }

  gatherStudents() {
    this.roomQty -= 3;
  }
}

const myRoom = new room(10, 4);

当我使用console.log记录时，我收到一条未定义的消息。

console.log(myRoom.changeStudy('language'));
console.log(myRoom.gatherStudents());
console.log(myRoom.changeStudy('math'));

如何调用这些功能并将结果打印到控制台。

Answer 1

您的代码存在一些问题。主要问题是你的方法没有返回任何东西，你的“超级”类没有实现引用的方法：

class school {
  constructor(size = '10', subjects = {math: 'green', physics: 'green', language: 'orange', history: null}) {
  this.size = size;
  this.subjects = subjects;
  this.classCode = null;
  this.study = null
}

changeStudy(study) {
  this.study = study
}

changeSubject(study) {
  this.classCode = this.subjects[study];
    if (super.study === 'math') {
      this.size += 1;
    }
  }
}

class room extends school {
  constructor(roomQty = 15, size, subjects) {
    super(size, subjects);
    this.roomQty = roomQty;
  }
  changeStudy(study) {
    super.changeStudy(study);
    if (this.study === 'math') {
      return this.roomQty += 1;
    } else {
      return 0
    }
  }

  gatherStudents() {
    return this.roomQty;
  }
} 

const myRoom = new room(10,4);

console.log(myRoom.changeStudy('language'));
console.log(myRoom.gatherStudents());
console.log(myRoom.changeStudy('math'));

es6日志记录功能未定义

1 个答案: