背景

最近在看antd源码，也在自学一些typescript的语法以及使用，然后准备带在学校的师弟做一个音乐播放器作为typescript的练习踩踩坑；

然后竟然没想到在项目刚开始就深陷大坑--搭建react-redux项目流程，一下内容就是记录我是怎样从这个深坑中爬出来的过程。

开始？根本开始不起来

从项目创建之后就掉坑里了。。。

创建项目

创建项目的流程很简单，可有参考我之前写的这篇文章

从mapStateToProps&mapDispatchToProps开始爬坑

刚开始还不是很熟悉typescript，所以我最开始的reducer, action, constant,文件都是以.js结尾，只有组件的代码是以.tsx结尾的，然后就开始按照流程，将store中的state进行mapStateToProps以及actions进行mapDispatchToProps，谁想到这竟然是噩梦的开始，最开始我是这样写的代码:

  import { bindActionCreators } from 'redux';function mapStateToProps(state: {}) {return {player: state.PlayerStore,};}function mapDispatchToProps(dispatch: Function) {return {playerActions: bindActionCreators(actions, dispatch)};}复制代码

然后就开始报错了。。。

几经折腾之后我又将代码改成了这样，才得以过关

  import { bindActionCreators, Dispatch } from 'redux';function mapStateToProps(state: { PlayerStore: object }) {return {player: state.PlayerStore,};}function mapDispatchToProps(dispatch: Dispatch<{}>) {return {playerActions: bindActionCreators<{}>(actions, dispatch)};}复制代码

爬坑react组件断言类型

  interface PlayerPropsClass {player: PlayerStateTypes;playerActions: actions.PlayerActionsTypes;}class Player extends React.Component<PlayerPropsClass, {}> {constructor(props: object) {super(props as PlayerPropsClass);this.state = {};}addOne = (num: number) => this.props.playerActions.count(num);subtractOne = (num: number) => this.props.playerActions.subtract(num);render() {const { countNumber } = this.props.player.toJS();return (<div className="player"><span>{countNumber}</span><button onClick={() => this.addOne(countNumber as number)}>点击+1</button><button onClick={() => this.subtractOne(countNumber as number)}>点击-1</button></div>);}}export default connect(mapStateToProps, mapDispatchToProps)(Player as any);复制代码

这里的(Player as any)报错提示

  [tslint] Type declaration of 'any' loses type-safety. Consider replacing it with a more precise type, the empty type ('{}'), or suppress this occurrence. (no-any)复制代码

然后我改成

  export default connect(mapStateToProps, mapDispatchToProps)(Player as {});复制代码

仍然报错

  [ts]类型“{}”的参数不能赋给类型“ComponentType<{ player: object; } & { playerActions: {}; }>”的参数。不能将类型“{}”分配给类型“StatelessComponent<{ player: object; } & { playerActions: {}; }>”。类型“{}”提供的内容与签名“(props: { player: object; } & { playerActions: {}; } & { children?: ReactNode; }, context?: any): ReactElement<any> | null”不匹配。复制代码

哇心态爆炸，都不知道怎么写这个断言。。。然后我想起了antd的一个例子，写的是React.ReactElement，然后偶然间在网上找到了说的是在node_modules中有一个@type文件夹就是typescript对于node包中的相应的类型匹配，于是我就按照这个路径node_modules/@types/react/index.d.ts，终于找到了React.ComponentType<T>，这个文件里面还有很多的类型，想要了解的可以自己去看看

  export default connect(mapStateToProps, mapDispatchToProps)(Player as React.ComponentType<PlayerPropsClass>);复制代码

爬坑action和reducer

有了以上的经验，再加上在这里看了一些代码，我决定把actions和reducer也改为ts结尾的文件；

• src/reducers/index.ts

    import { combineReducers, createStore } from 'redux';import PlayerStore from '../containers/Player/reducer';// 这个是用来使用到mapStateToProps函数的地方给state进行类型检测的export interface AppStoreType {PlayerStore: object;}const rootReducer = combineReducers({PlayerStore,});export default () => {return createStore(rootReducer);};复制代码

• containers/Demo/reducer.ts

    import * as PlayerTypes from './constant';import { fromJS } from 'immutable';// 由于使用到immutable，state上面就会使用到immutable的函数，所以需要将其也做成类型检测import { ImmutableFuncType } from '../../constant';interface ActionType {type: string;countNumber?: number;}interface StoreType {countNumber: number;}// 把当前容器的state组，然后抛出提供使用export type PlayerStateTypes = StoreType & ImmutableFuncType;const PlayerStore: PlayerStateTypes = fromJS({countNumber: 0,});export default (state = PlayerStore, action: ActionType) => {switch (action.type) {case PlayerTypes.COUNT:return state.update('countNumber', () => fromJS(action.countNumber));default:return state;}};复制代码

• containers/Demo/action.ts

    import * as PlayerTypes from './constant';export const count = (num: number) => ({type: PlayerTypes.COUNT,countNumber: num + 1,});export const subtract = (num: number) => ({type: PlayerTypes.COUNT,countNumber: num - 1,});// 抛出actions函数的类型以供mapDispatchToProps使用export interface PlayerActionsTypes {count: Function;subtract: Function;}复制代码

• containers/Demo/index.tsx

    import * as React from 'react';import './style.css';import { connect } from 'react-redux';import { bindActionCreators, Dispatch } from 'redux';import * as actions from './action';import { PlayerStateTypes } from './reducer';import { AppStoreType } from '../../reducers';interface PlayerPropsClass {player: PlayerStateTypes;playerActions: actions.PlayerActionsTypes;}function mapStateToProps(state: AppStoreType) {return {player: state.PlayerStore,};}function mapDispatchToProps(dispatch: Dispatch<{}>) {return {playerActions: bindActionCreators<{}>(actions, dispatch)};}class Player extends React.Component<PlayerPropsClass, {}> {constructor(props: object) {super(props as PlayerPropsClass);this.state = {};}addOne = (num: number) => this.props.playerActions.count(num);subtractOne = (num: number) => this.props.playerActions.subtract(num);render() {const { countNumber } = this.props.player.toJS();return (<div className="player"><span>{countNumber}</span><button onClick={() => this.addOne(countNumber as number)}>点击+1</button><button onClick={() => this.subtractOne(countNumber as number)}>点击-1</button></div>);}}export default connect(mapStateToProps, mapDispatchToProps)(Player as React.ComponentType<PlayerPropsClass>);复制代码

结尾

通过这个小练习还真的是感受到了typescript的好处，那就是在编译时就报错，而且能够知道报错原因，不需要在编译完成以后再去进行错误点的查找，确实节省了很多时间，尤其是对于JavaScript代码的undefined和null的处理很友好。。总之，感觉写起来很流畅啊。啊哈哈哈哈~~~