Dispatch is not a function useContext/useReducer React hooks

Question

My Home.js component just doesn't seem to see the dispatch function at all. Do you guys know why? I'm kinda new to redux style state management stuff in redux.

I keep getting the error "TypeError: dispatch is not a function"

App.js

import React from 'react';
import { HashRouter, Route } from 'react-router-dom';

import Home from './pages/Home';
import Start from './pages/Start';
import Result from './pages/Result';

import RPSContextProvider from './contexts/RPSContext';

const App = () => {
    return (
        <HashRouter>
            <RPSContextProvider>
                <Route exact path="/" component={Home} />
                <Route path="/start" component={Start} />
                <Route path="/result" component={Result} />
            </RPSContextProvider>
        </HashRouter>
    );
};

export default App;

Home.js

import React, { useRef, useContext } from 'react';
import { RPSContext } from '../contexts/RPSContext';
import './home.css';

const Home = (props) => {
    const { state, dispatch } = useContext(RPSContext);
    const playerNameEntry = useRef();

    const handleClick = () => {
        if (!isStringEmpty(playerNameEntry.current.value)) {
            dispatch({ type: 'SET_NAME', state: playerNameEntry.current.value });
            props.history.push({
                pathname: '/start'
            });
            console.log(dispatch);
        }
    };

    const isStringEmpty = (string) => string.trim().length === 0;

    return (
        <div className="app-container">
            <h1>
                You dare battle me at
                <br />
                Rock, Paper, Scissors?
                <br />
                You got no chance, kid!
            </h1>
            <p>What's your name, ya chancer?</p>
            <input type="text" onKeyPress={(e) => handleKeyPress(e)} ref={playerNameEntry} />
            <button onClick={handleClick}>Start</button>
        </div>
    );
};

export default Home;

RPSContext.js

import React, { createContext, useReducer } from 'react';
import { RPSReducer } from '../reducers/RPSReducer';

export const RPSContext = createContext();

const RPSContextProvider = (props) => {
    const [ state, dispatch ] = useReducer(RPSReducer, { playerName: '' });

    return <RPSContext.Provider value={{ state, dispatch }}>{props.children}</RPSContext.Provider>;
};

export default RPSContextProvider;

RPSReducer.js

export const RPSReducer = (state, action) => {
    switch (action.type) {
        case 'SET_NAME':
            return { playerName: action };
        default:
            throw new Error();
    }
};

Basically as a first step I just want to set the name of the entry. I know this is quite a lot of code just for what I'm doing, but just wanting to try out useReducer and useContext so that I can learn all this new stuff in React.

score 3 · Answer 1 · answered Sep 27 '19 at 14:51

I solved the problem by adding

    switch (action.type) {
        case 'SET_NAME':
            return { ...state, playerName: action.payload }

in my reducer, and in Home.js changed the state key I had in there to payload. Not 100% sure if it having the same name was effecting anything, but its much less confusing naming it payload.

    const handleClick = () => {
        if (!isStringEmpty(playerNameEntry.current.value)) {
            dispatch({ type: 'SET_NAME', payload: playerNameEntry.current.value });

score 3 · Answer 2 · answered Dec 17 '19 at 05:19

3

Wrap the whole App with AppContext.Provider passing with state and dispatch, like below

<AppContext.Provider value={{ state, dispatch }}>
  <div className="App">
    <Compo />
  </div>
</AppContext.Provider>

answered Dec 17 '19 at 05:19

Max

49
1
8

So you mean you can export dispatch from React? – Urasquirrel Jun 06 '21 at 03:03

Dispatch is not a function useContext/useReducer React hooks

2 Answers2