打字稿。是什么意思:(这和任何一样） [英] typescript. what is mean: (this as any)

问题描述

我遇到这段代码并且不明白它的作用：

I meet this code and do not understand exactly what it does :

public uploadItem(value:FileItem):void {
    let index = this.getIndexOfItem(value);
    let item = this.queue[index];
    let transport = this.options.isHTML5 ? '_xhrTransport' : '_iframeTransport';
    item._prepareToUploading();
    if (this.isUploading) {
      return;
    }
    this.isUploading = true;
    (this as any)[transport](item);
  }

任何人都可以解释这个（这个是什么）声明吗？

Can anyone explain what does this (this as any) statement do?

推荐答案

（这与任何一样）只是 类型断言 ，适用于开发/编译时间并且对运行时没有副作用，因为它纯粹是一个Typescript的东西。如果某些内容与这个相关，比如这个[what] 会输出错误，因为这个错误可以被抑制与（此为任何）[无论如何]

(this as any ) is just a Type Assertion that works on dev/compiling time and has no side effects on run time because it is purely a Typescript thing. It can be useful if something related to this like this[whatever] which outputs an error because this error can be suppressed with (this as any)[whatever]

同时 （这与任何一样）相当于（< any> this）

请注意： - suppressImplicitAnyIndexErrors 作为编译器选项可以抑制这些可能的错误。

Note to mention: --suppressImplicitAnyIndexErrors as a compiler option suppresses those kind of possible errors.

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