#基于React的createContext, useContext, useReducer封装的组合reducer库(优化了useCustomRedux成为一个泛型函数)

安装依赖库:

        npm i redux-custom

reducer.ts redux-custom.tsx test.tsx (使用案例,然后把组件直接引入到index.tsx中使用,使用JavaScript的大佬就把文件改一下除去一些类型定义等)

库代码如下:

import React, { Context, FC, createContext, useContext, useReducer, Dispatch, Reducer } from 'react';
/** 
 * @createContext ProviderContext 一个创建完毕的context
*/
const ProviderContext: Context<any> = createContext('provider');
/** 高阶函数
 *  @param reducer 传入一个整合或者没有整合的reducer
 *  @param initialState 传入一个初始化的state，用来当做默认值
 *  @genericity 类型R 定义reducer的类型,可选参数
 *  @genericity 类型T state的类型,可选参数
 */
export default (reducer: Function, initialState: any, init?: any) => (Com: FC<any>) => {
        return () => {
            const [state, dispatch] = useReducer<any>(reducer, initialState, init);
            return (
                <ProviderContext.Provider value={{ state, dispatch }}>
                    <Com />
                </ProviderContext.Provider >
            );
        }
    }
/**
 *      获取自定义的redux
 *  @state 这个参数是需要拿来使用的state 
 *  @dispatch 这个参数是dispatch分发action使用的
 *  @T 接收一个state的类型，是总体的state的类型,可选参数
 */
export function useCustomRedux<T>() {
    interface Type {
        dispatch: Dispatch<T>;
        state: T;
    }
    return useContext<Type>(ProviderContext);
}
/**接受一个包含多个reducer函数的对象，返回一个新的reducer函数
 * @param reducers 传入多个reducer,用于整合成一个reducer
 */
export function combineReducers(reducers: any) {//整合reducer函数的对象的函数
    return function (state = {}, action: any) {//返回一个整合之后的reducer函数 ,然后传给了createStore使用
        //依次调用所有的reduce函数，并得到了状态,然后得到了许多的状态,得到n个新的子状态，封装成对象并返回
        return Object.keys(reducers).reduce((newState: any, key: string | number) => {
            try {
                newState[key] = reducers[key]((state as any)[key], action);//然后得到新的子状态，赋值给对应的key的新state里面
            } catch (error) {
                console.error('传入的state的key必须和每个reducer的key一致');
            }
            return newState;
        }, {});
    }
}

使用方式:

reducer.ts文件

import { combineReducers } from './redux-custom';
const initialReucer1 = {
    count: 1
}
const initialReucer2 = {
    user: {}
}
function reducer1(state = initialReucer1, action: any) {
    switch (action.type) {
        case 'ADD_COUNTER':
            return { ...state, count: state.count + 1 }
        default:
            return state;
    }
}
function reducer2(state = initialReucer2, action: any) {
    switch (action.type) {
        default:
            return state;
    }
}

export const reducer = combineReducers({ reducer1, reducer2 });//合并reducer
export const initialState = { reducer1: initialReucer1, reducer2: initialReucer2 };//合并initialState

test.tsx

import React from 'react'
import provider, { useCustomRedux } from './redux-custom';
import { reducer, initialState } from './reducer';
function Test() {
    //优化
    const { state, dispatch } = useCustomRedux<typeof initialState>();
    // const { state, dispatch } = useCustomRedux();
    return (
        <div>
            <h2>{state.reducer1.count}</h2>
            <button onClick={() => dispatch({ type: 'ADD_COUNTER' })}>触发dispatch-action</button>
        </div>
    )
}
export default provider(reducer, initialState)(Test);