TypeError: middleware is not a function

问题

I'm trying to apply redux in my reactjs app. I can't proceed because of these errors:

I'm sure that I already installed all the dependencies that I need. Here is a relevant part of my package.json

"dependencies": {
   "react-redux": "^5.0.6",
   "redux": "^3.7.2",
   "redux-logger": "^3.0.6",
   "redux-promise": "^0.5.3",
   "redux-thunk": "^2.2.0",
}

Here is a part of my index.js that implements redux

import { createStore, applyMiddleware } from 'redux';
import { Provider } from 'react-redux';
import thunkMiddleware from 'redux-thunk';
import createLogger from 'redux-logger';
import reducers from './reducers';

const logger = createLogger();
const store = createStore(reducers,
    applyMiddleware(
        thunkMiddleware, logger
    )
)

ReactDOM.render(
    <Provider store={store}>
        <App />
    </Provider>,
    document.getElementById('root')
);

回答1:

According to the docs you are mixing up the usage of redux-logger

You either need to import the specific createLogger function

import { createLogger } from 'redux-logger'

const logger = createLogger({
  // ...options
});

Or use the default import

import logger from 'redux-logger'

And then your code should be fine

const store = createStore(
  reducers,
  applyMiddleware(thunkMiddleware, logger)
)

回答2:

I don't see react and react-dom in your dependencies, and it is not included in the import statements.

Let me provide you with an example of how I did an App recently, also using the redux developer tools which is amazing.

import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from 'react-redux';
import { createStore, combineReducers, applyMiddleware, compose } from 'redux';
import reduxThunk from 'redux-thunk';
import App from './components/App';
import authReducer from '../reducers/auth';
import urlsReducer from '../reducers/urls';

const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;

//Store creation
  const store = createStore(
    combineReducers({
      auth: authReducer,
      urls: urlsReducer
    }),
    composeEnhancers(applyMiddleware(reduxThunk))
  );

ReactDOM.render(
      <Provider store={store}>
        <App />
      </Provider>,
      document.getElementById('root')
    );

I would figure that you just need to add logger, after reduxThunk. And if you have already combined your reducers, then just provide reducers instead of combineReducers.

Regards, Rafael

回答3:

the easiest way to fix the issue

import * as thunk from 'redux-thunk';



createStore(rootReducer, InitialState, applyMiddleware(thunk.default));

回答4:

I was getting the same error TypeError: middleware is not a function.

import { createStore, combineReducers, applyMiddleware } from "redux";
import { createLogger } from "redux-logger";
import thunk from "redux-thunk";

import math from "./reducers/mathReducer";
import user from "./reducers/userReducer";

const logger = createLogger();

export default createStore(
  combineReducers({ math, user }),
  {},
  applyMiddleware(logger, thunk)
);

Replacing applyMiddleware(logger, thunk) with applyMiddleware(logger, thunk.default) worked for me.

回答5:

I was trying to add logger to the list of middleware only in development but messed up the import and received the same error. To fix my issue, I needed to add .default to the require():

const middleware = []

if (process.env.NODE_ENV === 'development') {
  middleware.push(require('redux-logger').default)
}

来源：https://stackoverflow.com/questions/46869671/typeerror-middleware-is-not-a-function

标签

reactjs

redux

react-redux

redux-thunk