DOM 事件没有 'target' 属性 如果处理为 'Object' - Atom 说

DOM Event has no 'target' property if handled as 'Object' - Atom says

在模板中:

<input (change)="changed($event)" ...

在 TypeScript 文件中:

private changed(event: Object): void {
...event.target.value...
}

Atom 显示以下错误:

Property 'target' does not exist on type 'Object'.

为什么?

如果我删除 : Object,一切都会很好。在那里提到 : Object 甚至根本没有必要。我只是想知道什么会导致此错误消息..

事件的类型应该是 Event -- 这是包含 target 属性:

private changed(event: Event): void {
    // You can access `event.target` here.
    // If you want to access event.target.value you have to assert event.target as `HTMLInputElement` because not all event targets are input elements:
    var value = (event.target as HTMLInputElement).value;
}