什么 Typescript 类型是更改事件?(角度) [英] What Typescript type is a change event? (In Angular)

问题描述

我正在尝试找出 Angular 项目中使用的更改事件的 Typescript 类型.

I'm trying to figure out what Typescript type a change event is used in an Angular project.

代码很简单:

file-upload.component.html

<input type="file" (change)="onChange($event)"/>

file-upload.ts

public onChange(event: Event): void {
  if (event.target.files && event.target.files.length) {
    const [file] = event.target.files;
    console.log(file);
  }
}

将事件输入为 Event 会给我以下 Typescript linting 错误:

Typing the event as Event gives me the following Typescript linting error:

Property 'files' does not exist on type 'EventTarget'

如果不是Event，我应该输入什么?

What should I be typing this if not Event?

推荐答案

这是一个事件.但是您将不得不将您使用的常量转换为 HTMLInputElement.

It is an event. But you're going to have to cast the const you're using as an HTMLInputElement.

public onChange(event: Event): void {
  if ((event.target as HTMLInputElement).files && (event.target as HTMLInputElement).files.length) {
    const [file] = event.target.files;
  }
}

唯一的另一种方法是使用 tsignore 抑制错误.在 react 和 flow 中，它们有一个 SyntheticEvent 类型，您可以输入这个特殊情况来绕过它，但 angular 没有真正的等价物.

The only other way is going to be to suppress the error with tsignore. In react, flow, they have a type SyntheticEvent that you can type this particular case as to get around it but angular doesn't have a real equivalent.

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