来自https://github.com/DefinitelyTyped/DefinitelyTyped/blob/15b7bac31972fbc081028937dfb1487507ca5fc9/types/react/index.d.ts#L199-L200
interface Component<P = {}, S = {}> extends ComponentLifecycle<P, S> { }道具和状态被初始化为
{}，因此对于没有状态或道具的组件，我们可以简单地执行以下操作：class Foo extends React.Component {}
