Question

我有一个基类,即<代码>abstract, 延伸至HTMLElement, 称CustomElementRegistry.define。打字像使用<条码>,即,作为第二个论点,因为基类为<条码>。但是,这似乎不正确,因为最后一类显然永远不会抽象。我不得不使用下面的ug。是否有更好的办法这样做?

abstract class CustomElement extends HTMLElement {
  constructor() {
    super();
  }
  // Without a cast, the `this` argument gets this error:
  // tsbug.ts:12:6 - error TS2345: Argument of type  this  is not assignable to parameter of type  CustomElementConstructor .
  //   Type  CustomElement  is not assignable to type  CustomElementConstructor .
  //     Type  CustomElement  provides no match for the signature  new (...params: any[]): HTMLElement .
  register() {
    customElements.define(
     "custom-element",
     this, // This argument gets the error.
     // If you replace the above `this` argument with the one below, it works.
     // this as unknown as new () => HTMLElement,
     {});
  }
}

class MyElement extends CustomElement {
  constructor() {
    super();
    this.register();
  }
}

const e = new MyElement();

Answer 1

What you are trying to do is incorrect. An instance of CustomElement should not be trying to register itself with custom elements. That logic is on a higher-level than what belongs inside the class.

考虑如果你写的话会发生什么情况

const a = new MyElement();
const b = new MyElement();

两者都试图登记,并在海关要素登记处重新登记。此外,每当你试图在你的标记中使用习俗要素时,都会发生这种情况。这并不好。

相反,你的法典应当模仿更接近于:

customElements.define("custom-element", MyElement, {});
const a = new MyElement();
const b = new MyElement();

Design issues aside, what you are looking for is not possible to do within a proper OO paradigm.

某类人没有静态地提到自己,可以动态地加以利用。文本正确地指出了一个问题:

customElements.define(
     "custom-element",
     this, 
// This is a reference to an *instance* of a class, not to a constructor. 
/// Casting will not make it work. You need a reference to the class you want to register.
     {});

Answer 2

The second argument of customElements.define must be an instance of CustomElementConstructor, which is defined in "lib.dom.d.ts" as follows:

interface CustomElementConstructor {
    new(...params: any[]): HTMLElement;
}

So, your code errors because, instead of passing a constructor as second argument, you are passing an instance of (a subclass of) HTMLElement.

尽管如此,这只是而不是界定和登记习俗超文本元素的正确方式。如果你(在评论中)问,作为开端人,这里的链接是相关文件的链接:。

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