javascript - 如何将链函数从一个类添加到另一个类？

Question

我正在尝试用 JS 开发一个供个人使用的游戏引擎。我想让我的引擎能够使用单独类的元素。我试图解决的一个这样的问题是将方法从一个类(比如一个链接函数的数学类)链接到我的主要函数。

这是我希望它看起来像的示例:

let game = new Engine()
game.operator(5).sum(3).divide(2)

这可能是我的代码中的内容，尽管这是我不确定要做什么的地方。

class Engine {
   constructor() {
    //Set up engine here
    /* This is where I am unsure how to link the following operator class to this one. 
    * Do I put it here in constructor or ...
    */

   }
   /* ... do I put it here? (Or not in this class at all?)
   *
   * This is what I tried doing as a function
   *
   * operator(input) {
   *    let op = new Operator(input);
   * }
   */
}
class Operator {
    /*The following class is different than the one I am using, but follows similar syntax: 
    * Basic usage: operator(5).sum(3, 4) => Should output 12
    * How the class works is mostly irrelevant, just know it chains methods.
    */
    constructor(input) {
        this.input = input;
        this.answer = this.input;
    }
    sum() {
        let a = arguments[0]
        for(var i = 1; i < arguments.length; i++) {
            a += arguments[i];
        }
        this.answer += a;
        return this;
    }
    divide() {
        let a = arguments[0];

        for(var i = 1; i < arguments.length; i++) {
            a *= arguments[i];
        }
        this.answer /= a;
        return this;
    }

}

我怎样才能让一个类能够链接来自不同类的方法？

Answer 1

链接模式是让实例保持链状态，并提供返回链状态的“值”方法。要在两个类之间进行链接，我想我会包含一个返回另一个类实例的特殊值方法。 (为了让读者保持导向，将其命名为指示类型更改的名称)...

class ObjectA {
  constructor(string) {
    this.chainValue = string
    this.string = string
  }

  transformA() {
    this.chainValue = this.chainValue.toUpperCase()
    return this
  }

  transformB() {
    this.chainValue = this.chainValue + "bar"
    return this
  }

  // the regular value method
  get value() {
    return this.chainValue
  }

  // like the value method, but named to explicitly return MyNumber
  get numberValue() {
    return new MyNumber(this.value.length)
  }
}

class MyNumber {
  constructor(int) {
    this.chainValue = int
    this.int = int
  }
  
  add(n) {
    this.chainValue += n
    return this
  }
  
  get value() {
    return this.chainValue
  }
}

let a = new ObjectA("foo")
console.log(
  a
  .transformB()   // append "bar"
  .transformA()   // convert to upper case
  .numberValue    // return a number (arbitrarily, the length of the chain state)
  .add(12)        // add 12
  .value          // expect 18
)