next-redux-wrapper

What is next-redux-wrapper?

The next-redux-wrapper package is a utility that helps integrate Redux with Next.js applications. It simplifies the process of setting up Redux in a Next.js environment by providing a higher-order component (HOC) that can wrap the Next.js App component, ensuring that the Redux store is properly initialized and available throughout the application.

What are next-redux-wrapper's main functionalities?

Store Initialization

This feature allows you to initialize a Redux store and wrap your Next.js application with it. The `createWrapper` function from next-redux-wrapper is used to create a wrapper that can be applied to the Next.js App component.

import { createStore } from 'redux';
import { createWrapper } from 'next-redux-wrapper';

const reducer = (state = { count: 0 }, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return { ...state, count: state.count + 1 };
    default:
      return state;
  }
};

const makeStore = () => createStore(reducer);

export const wrapper = createWrapper(makeStore);

Server-Side Rendering (SSR) with Redux

This feature demonstrates how to use next-redux-wrapper to handle server-side rendering with Redux. The `getServerSideProps` function is wrapped with `wrapper.getServerSideProps`, allowing you to dispatch actions and access the Redux store on the server side.

import { wrapper } from '../store';

const Page = ({ count }) => (
  <div>
    <h1>Count: {count}</h1>
  </div>
);

export const getServerSideProps = wrapper.getServerSideProps((store) => async () => {
  store.dispatch({ type: 'INCREMENT' });
  return { props: { count: store.getState().count } };
});

export default Page;

Static Site Generation (SSG) with Redux

This feature shows how to use next-redux-wrapper for static site generation with Redux. The `getStaticProps` function is wrapped with `wrapper.getStaticProps`, enabling you to dispatch actions and access the Redux store during the build process.

import { wrapper } from '../store';

const Page = ({ count }) => (
  <div>
    <h1>Count: {count}</h1>
  </div>
);

export const getStaticProps = wrapper.getStaticProps((store) => async () => {
  store.dispatch({ type: 'INCREMENT' });
  return { props: { count: store.getState().count } };
});

export default Page;

Other packages similar to next-redux-wrapper

next-redux-saga

The next-redux-saga package integrates Redux-Saga with Next.js. It provides a similar HOC to wrap the Next.js App component, but it focuses on managing side effects using Redux-Saga. Compared to next-redux-wrapper, it adds the capability to handle complex asynchronous flows with sagas.

next-redux-cookie-wrapper

The next-redux-cookie-wrapper package extends next-redux-wrapper by adding support for persisting Redux state in cookies. This is useful for maintaining state across server and client in a Next.js application. It offers similar functionality to next-redux-wrapper but with added state persistence capabilities.

README

Redux wrapper for Next.js

Usage

npm install next-redux-wrapper --save

Wrapper has to be attached your page components (located in /pages). For safety it is recommended to wrap all pages, no matter if they use Redux or not, so that you should not care about it anymore in all child components.

Here is the minimal setup (makeStore and reducer usually are located in other files):

import React, {Component} from "react";
import {createStore} from "redux";
import withRedux from "next-redux-wrapper";

const reducer = (state = {foo: ''}, action) => {
    switch (action.type) {
        case 'FOO':
            return {...state, foo: action.payload};
        default:
            return state
    }
};

const makeStore = (initialState) => {
    return createStore(reducer, initialState);
};

class Page extends Component {
    static getInitialProps({store, isServer, pathname, query}) {
        store.dispatch({type: 'FOO', payload: 'foo'}); // component will be able to read from store's state when rendered
        return {custom: 'custom'}; // you can pass some custom props to component from here
    }
    render() {
        return (
            <div>
                <div>Prop from Redux {this.props.foo}</div>
                <div>Prop from getInitialProps {this.props.custom}</div>
            </div>
        )
    }
}

Page = withRedux(makeStore, (state) => ({foo: state.foo}))(Page);

export default Page;

How it works

No magic is involved, it auto-creates Redux store when getInitialProps is called by Next.js and then passes this store down to React Redux's Provider, which is used to wrap the original component, also automatically. On the client side it also takes care of using same store every time, whereas on server new store is created for each request.

The withRedux function accepts makeStore as first argument, all other arguments are internally passed to React Redux's connect() function for simplicity. The makeStore function will receive initial state as one argument and should return a new instance of redux store each time when called, no memoization needed here, it is automatically done inside the wrapper.

Async actions in getInitialProps

function someAsyncAction() {
    return {
        type: 'FOO',
        payload: new Promise((res) => { res('foo'); })
    }
}

function getInitialProps({store, isServer, pathname, query}) {
    
    // lets create an action using creator
    const action = someAsyncAction();
    
    // now the action has to be dispatched
    store.dispatch(action);
    
    // once the payload is available we can resume and render the app
    return action.payload.then((payload) => {
        // you can do something with payload now
        return {custom: 'custom'}; 
    });
    
}