类对象重叠

Question

我仍然在努力学习，我试图让一群演员加入电影类，我让它发挥作用，但我仍然有问题，因为如果你增加另一个演员，最后一个消失了，我尝试了一个循环，但我什么也做不了。

​

class Movie {
    constructor(title,year,duration){
        this.title = title;
        this.year = year;
        this.duration = duration;
    }

    addCast(actors){
        this.actors = actors
    }
}     
class Actor {
    constructor(name,age)
    {  
        this.name = name;
        this.age = age;
    }
}

const terminator = new Movie('Terminator I', 1985, 60);
const arnold = new Actor('Arnold Schwarzenegger', 50);
const otherCast = [
    new Actor('Paul Winfield', 50),
    new Actor('Michael Biehn', 50),
    new Actor('Linda Hamilton', 50)
];
//From here it can not be modified
    let movieOne = new Movie("Kong","2018","2h30m");
    let movieTwo = new Movie("Joker","2019","2h03m");
    let movieThree = new Movie("John Wick 3", "2019", "1h49m");
    terminator.addCast(arnold);
    terminator.addCast(otherCast);
//To here it can not be modified
    console.log({movieOne,movieTwo,movieThree,terminator});

​

看见?阿诺德也应该在演员中，但事实并非如此！谢谢你提前帮忙。

另一件事，这是为了一个节选，我不能修改我评论的行。

Answer 1

你有

addCast(actors){
    this.actors = actors
}

这并不会将传递的参与者数组添加到实例上的actors --它用传递的参数替换实例的actors。调用addCast将导致丢失以前在actors上存在的任何内容。

为了帮助减少bug，它可以帮助适当地命名方法--对于这样的逻辑，我称之为setCast，而不是addCast。

如果要将参数添加到现有强制转换的末尾，并且不确定参数是要添加的单个参与者还是要添加的参与者数组，请使用以下命令：

  addCast(actorOrActors) {
    if (Array.isArray(actorOrActors)) {
      this.actors.push(...actorOrActors);
    } else {
      this.actors.push(actorOrActors);
    }
  }

​

class Movie {
  constructor(title, year, duration) {
    this.title = title;
    this.year = year;
    this.duration = duration;
    this.actors = [];
  }

  addCast(actorOrActors) {
    if (Array.isArray(actorOrActors)) {
      this.actors.push(...actorOrActors);
    } else {
      this.actors.push(actorOrActors);
    }
  }
}
class Actor {
  constructor(name, age) {
    this.name = name;
    this.age = age;
  }
}

const terminator = new Movie('Terminator I', 1985, 60);
const arnold = new Actor('Arnold Schwarzenegger', 50);
const otherCast = [
  new Actor('Paul Winfield', 50),
  new Actor('Michael Biehn', 50),
  new Actor('Linda Hamilton', 50)
];
//From here it can not be modified
let movieOne = new Movie("Kong", "2018", "2h30m");
let movieTwo = new Movie("Joker", "2019", "2h03m");
let movieThree = new Movie("John Wick 3", "2019", "1h49m");
terminator.addCast(arnold);
terminator.addCast(otherCast);
//To here it can not be modified
console.log({
  movieOne,
  movieTwo,
  movieThree,
  terminator
});

​

Answer 2

这是因为在addCast()方法中，每次调用它时，都要替换以前的值，而不是追加它

Answer 3

你用第二个addActors电话覆盖了阿诺德。一次只向一组演员添加一个演员。

class Movie {
constructor(title,year,duration){
    this.title = title;
    this.year = year;
    this.duration = duration;
    this.actors = [];
}


addCast(actor){
    this.actors.push(actor);
}

terminator.addCast(arnold);
terminator.addCast(otherCast[0]);
terminator.addCast(otherCast[1]);
terminator.addCast(otherCast[2]);