声明一个扩展另一个多态类别的多态类别

Question

我正在编写一个希望接收一个组件的组件，该组件拥有一个特定字段onPropChange，可以通过REF访问，作为Prop。

/* @flow */
import * as React from 'react';
type onPropChangeObject<Props> = {
    [key: $Keys<Props>]: (newValue: any) => void
}
declare class PropWatchableComponent<DefaultProps, Props: Object, State> 
    extends React.Component<DefaultProps, Props, State> 
{
    onPropChange?: onPropChangeObject<Props>;
}

但是，在最新版本的流（0.39.0）中，类型检查失败了，如下所示

8: declare class PropWatchableComponent<DefaultProps, Props: Object, State> extends React.Component<DefaultProps, Props, State> {   ^ undefined. Did you forget to declare some incompatible instantiation of `DefaultProps`?. This type is incompatible with
8: declare class PropWatchableComponent<DefaultProps, Props: Object, State> extends React.Component<DefaultProps, Props, State> {   ^ some incompatible instantiation of `DefaultProps`
8: declare class PropWatchableComponent<DefaultProps, Props: Object, State> extends React.Component<DefaultProps, Props, State> {   ^ undefined. Did you forget to declare some incompatible instantiation of `State`?. This type is incompatible with
8: declare class PropWatchableComponent<DefaultProps, Props: Object, State> extends React.Component<DefaultProps, Props, State> {   ^ some incompatible instantiation of `State`
8: declare class PropWatchableComponent<DefaultProps, Props: Object, State> extends React.Component<DefaultProps, Props, State> {
                                        ^ DefaultProps. This type is incompatible with
8: declare class PropWatchableComponent<DefaultProps, Props: Object, State> extends React.Component<DefaultProps, Props, State> {
                                        ^ undefined. Did you forget to declare DefaultProps?
8: declare class PropWatchableComponent<DefaultProps, Props: Object, State> extends React.Component<DefaultProps, Props, State> {
                                                                     ^ State. This type is incompatible with
8: declare class PropWatchableComponent<DefaultProps, Props: Object, State> extends React.Component<DefaultProps, Props, State> {
                                                                     ^ undefined. Did you forget to declare State?

所有这些关于未定义的谈论是什么？我显然将DefaultProps和State称为类型参数。我忘记了什么？

Answer 1

请参阅此内容，您应该使用interface而代替'class'。