打字稿：类中的扩展集会导致错误（构造函数集需要“新”） [英] Typescript: Extending Set in class causes error (Constructor Set requires 'new')

问题描述

我正在尝试对Set对象执行一些基本操作，例如此处

I'm trying to implement some basic operations to the Set object like says here

这是代码

export class Conjunto extends Set<any>{
  constructor(initialValues?) {
    super();
    return new Conjunto(initialValues);
  }

  isSuperset(subset) {
    //some code
  }
}

你们有什么想法使它起作用吗？还是我做错了什么？

Do you guys have any idea to make it work? or am I doing something wrong?

目前，我正在使用这个家伙，发现这个家伙此处

For the moment I'm using the hack this guy found here

推荐答案

如果要向其中添加函数Set原型，或向Set添加polyfills，您可以执行以下操作：

if you are trying to add functions to the Set prototype, or add polyfills to Set, you can do the following:

declare global {
  interface Set<T> {
      // polyfill
      isSuperset(subset: Set<T>) : boolean;
      // new function
      someNewFunc(): boolean;
  }
}

// add polyfill to the Set prototype as mentioned in the doc you provided: https://developer.mozilla.org/es/docs/Web/JavaScript/Referencia/Objetos_globales/Set 
Set.prototype.isSuperset = function(subset) {
    for (var elem of subset) {
        if (!this.has(elem)) {
            return false;
        }
    }
    return true;
}

//add the new someNewFunc;
Set.prototype.someNewFunc = function() {
    // some logic here...
    return true;
}

要使用：

stringSet = new Set<string>()
stringSet.isSuperset(someOtherSet);
stringSet.someNewFunc(); // returns true

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