javascript - 如何使用 Typescript 在 react-redux 中正确使用 'connect'

Question

我在应用程序中使用 typescript，但发现 react-redux 存在一些问题。 'connect' 方法报告了一个问题，我不知道它，因为我是 typescript 和 redux 的新手。我应该做什么或应该修改我的代码中的什么地方？非常感谢

使用 typescript@3.3、react@16.8.5、react-redux@7.1.0 构建的应用程序。

// article
interface IArticle {
  title: string,
  author: string
}

// state
interface MyState {
  list: [],
  article: IArticle
}

// stateMapToProps
interface MyStateProps {
  article: IArticle
}

// router match
interface MatchParams {
  id: string
}

// own props
interface MyOwnProps extends RouteComponentProps < MatchParams > {
  article: IArticle,
  dispatch: (o: object) => {}
}

class ArticleContainer extends Component < MyOwnProps, {} > {
  constructor(props: MyOwnProps) {
    super(props);
  }

  componentDidMount() {
    const {
      dispatch
    } = this.props;
    const id = this.props.match.params.id
    dispatch(fetchArticle(id))
  }

  render() {
    const {
      article
    } = this.props;
    return ( <
      Article article = {
        article
      } > < /Article>
    )
  }
}

const mapStateToProps = (state: MyState): MyStateProps => {
  return {
    article: state.article
  }
}

export default connect < MyStateProps, {}, {
  article: IArticle
} > (
  mapStateToProps
)(ArticleContainer)

这是异步操作的代码 fetchArticle

function fetchArticle(id: string) {
  return function(dispatch: (action: AnyAction) => {}): Promise<void> {
    dispatch(getArticle(id))

    return axios.get(`/article/${id}`)
      .then(res => {
        dispatch(getArticleSuccess(res.data))
      })
  }
}

错误发生在export行，信息如下:

Argument of type '(state: MyState) => MyStateProps' is not assignable to parameter of type 'MapStateToPropsParam'. Type '(state: MyState) => MyStateProps' is not assignable to type 'MapStateToPropsFactory'. Types of parameters 'state' and 'initialState' are incompatible. Type '{}' is missing the following properties from type 'MyState': list, articlets(2345)

Answer 1

能够编译代码的最少步骤:

1. MyOwnProps 应该是

   import { AnyAction } from 'redux';
   
   interface AppThunkAction<TAction> {
       (dispatch: (action: TAction) => void, getState: () => MyState): any;
   }
   
   // As you're going to dispatch thunk actions, dispatch should be overloaded
   interface Dispatch<TAction> {
       (action: AppThunkAction<TAction>): any
       (action: TAction): TAction
   }
   
   // own props
   interface MyOwnProps extends RouteComponentProps<MatchParams> {
       article: IArticle,
       dispatch: Dispatch<AnyAction>
   }
   

2. 如果你想为 connect 函数提供类型，像这样添加 MyState 作为最后一个类型

   export default connect <MyStateProps, {}, {
           article: IArticle
       }, MyState >(
           mapStateToProps
   )(ArticleContainer)
   

   或者你可以让编译器自己推断类型，这是首选

   export default connect(
       mapStateToProps
   )(ArticleContainer)
   

这样的工作结果

import { Component } from 'react';
import { RouteComponentProps } from 'react-router-dom';
import { connect, ResolveThunks } from 'react-redux';
import { AnyAction } from 'redux';
import axios from 'axios';

// article
interface IArticle {
    title: string,
    author: string
}

// state
interface MyState {
    list: [],
    article: IArticle
}

// stateMapToProps
interface MyStateProps {
    article: IArticle
}

// router match
interface MatchParams {
    id: string
}

export interface AppThunkAction<TAction> {
    (dispatch: (action: TAction) => void, getState: () => MyState): any;
}

interface Dispatch<TAction> {
    (action: AppThunkAction<TAction>): any
    (action: TAction): TAction
}

// own props
interface MyOwnProps extends RouteComponentProps<MatchParams> {
    article: IArticle,
    dispatch: Dispatch<AnyAction>
}

function getArticle(id: string) {
    return {
        type: 'GET_ARTICLE',
        id
    }
}

function getArticleSuccess(i: any) {
    return {
        type: 'SET_ARTICLE',
        i
    }
}



const fetchArticle = (id: string): AppThunkAction<AnyAction> =>
    (dispatch, getState) => {
        dispatch(getArticle(id))

        return axios.get(`/article/${id}`)
            .then(res => {
                dispatch(getArticleSuccess(res.data))
            })
    }

class ArticleContainer extends Component<MyOwnProps, {}> {
    constructor(props: MyOwnProps) {
        super(props);
    }

    componentDidMount() {
        const {
            dispatch
        } = this.props;
        const id = this.props.match.params.id
        dispatch(fetchArticle(id))
    }

    render() {
        const {
            article
        } = this.props;
        return (<div>article: {article}</div>
          )
        }
      }

const mapStateToProps = (state: MyState): MyStateProps => {
  return {
                article: state.article
          }
        }

export default connect(
            mapStateToProps
)(ArticleContainer)