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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