React hook Redux usereducer usecontext enables Redux to be accessed from external JS


Create master file

  1. root directorysrcestablishreducerfolder
  2. Create under folderuseDataX.jsfile

import { createContext, useContext, useReducer } from "react";

//?  Thrown to create a context that can be accessed (via the value of DataContext. Provider)
export const DataContext = createContext({});

//?  Define initial value (used to create usereducer)
const creatData = {

//?  Thrown, the method can be accessed in ordinary JS
export function dispatchRef(value){
    return {
      current: value

//?  This form is called reducer (the value transmitted through usereducer, receiving state: original value (after changing createdata), action: changed value (the value transmitted from dispatch)
function reducer(state, action) {
    Let stateclone = {... State} // deep copy copy is required here. You can use json.parse (JSON. Stringify (state)) to convert it
    return stateClone

//?  Thrown to get the value in the DataContext
export function useData(){
  const { Xdata } = useContext(DataContext);
  return Xdata;

//Main function (can wrap root component)
export function GlobalLoadingProvider(props) {
  //Todo usereducer accepts a reducer function as a parameter, and reducer accepts two parameters, one is state and the other is action.
  //Todo then returns a status count and dispath. Count is the value in the returned status, and dispatch is a that can publish events to update the state.
  //?  Update dataarr after modifying dispath!
  const [dataArr, dispatch] = useReducer(reducer, creatData);
  //?  Access in normal JS
  dispatchRef.current = dispatch;
  return (
    <DataContext.Provider value={{ Xdata: dataArr, dispatch }}>


  1. index.jsAdd package label to main entry file<GlobalLoadingProvider></GlobalLoadingProvider>
import React from "react";
import ReactDOM from "react-dom";
import "./index.css";
import App from "./App.jsx";
// import reportWebVitals from './reportWebVitals';
import { GlobalLoadingProvider } from "./reducer/useDataX";
      <App />
  1. get data
import { useData } from "./reducer/useDataX";
function Test() {
  const { loading } = useData();
  return <div>{loading}</div>;
export default Test;
  1. Modify data in component
import React, { useContext } from "react";

import { DataContext } from "./reducer/useDataX";
function Test() {
  const { dispatch } = useContext(DataContext);
  return (
        onClick={() => {
          dispatch({ type: "loading", value: true });
export default Test;
  1. Common JS modify data
import { dispatchRef } from "../reducer/useDataX";


That’s it. Pay attention to whether the path is correct when referencing. Now the main files are written together, and some encapsulation can be done after the business logic is complex.

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