javascript - ES6类构建

Question

我想问你关于JavaScript、ES6中类构造的问题。可以将类名放在从“母类”扩展的其他类的构造函数中吗？ (有点迷糊……)

  class Brick {
    constructor(x,y,graphic,width,height,type,live, speed){
      this.x = x
      this.y = y
      this.graphic = graphic
      this.width = width
      this.height = height
      this.type = type
      this.live = live
      this.speed = speed
  }
  print(){
      console.log(this.y)
      console.log(this.x)
      console.log(this.graphic)
      console.log(this.width)
      console.log(this.height)
      console.log(this.type)
      console.log(this.live)
    }
  init(){
    console.log('added to board')
  }
}

现在，我想让类 wchih 从 Brick 类扩展为:

  class BrickRed extends Brick {
    constructor(Brick){
      super(...arguments)
      this.graphic = "red.jpg"
      this.live = 15
    }
  }

我不确定它是否可以，因为我找不到任何像上面那样呈现的教程。正是这两行:constructor(Brick) 和 super(...arguments)

根据我看到的教程，最好(也是唯一)的选择是这样做:

class BrickBlue extends Brick {
    constructor(x,y,graphic,width,height,type,live, speed){
      super(x,y,graphic,width,height,type,live, speed)
      this.graphic = "blue.jpg"
      this.live = 10
    }
  }

但这看起来很难看，我想改进它。

Answer 1

Is this ok to put class name inside constructor of other class which extends from "mother class"?

没有。正确的方法是你的第二个片段。但是，如果 BrickBlue 硬编码了一些 props，则无需在构造函数中传递它们:

class BrickBlue extends Brick {
    constructor(x,y,width,height,type,speed){
      super(x,y,"blue.jpg",width,height,type,10,speed)
    }
  }

如果你正在寻找类似的东西

class BrickBlue extends Brick {
    constructor(args-of-Brick)

没有这样的东西。

But this looks ugly, and I want to improve it.

是的，长参数列表很难看，而且由于 JS 尚不支持命名参数，因此您无能为力。但是，您可以考虑将相关参数分组到单独的对象中:

class Brick {
   constructor(position, graphic, size, type, behaviour) 

其中 position 类似于 {x:10, y:20} 等

另一种选择是提供一个对象的整个参数列表，从而模仿命名参数:

class Brick {
    constructor({x, y, graphic, width, height, type, live, speed}) {

...

new Brick({
  x: 1,
  y: 2,
  graphic: ...
  ...
})

在派生类中:

class BrickBlue extends Brick {
    constructor(args) {
        super({
            ...args,
            graphic: 'blue.jpg',
            live: 10
        })
    }