A HOC that brings Next.js and Redux together
Contents:
- Motivation
- Installation
- Usage
- How it works
- Tips and Tricks
- Upgrade from 6.x to 7.x
- Upgrade from 5.x to 6.x
- Upgrade from 1.x to 2.x
- Resources
Setting up Redux for static apps is rather simple: a single Redux store has to be created that is provided to all pages.
When Next.js static site generator or server side rendering is involved, however, things start to get complicated as another store instance is needed on the server to render Redux-connected components.
Furthermore, access to the Redux Store
may also be needed during a page's getInitialProps
.
This is where next-redux-wrapper
comes in handy: It automatically creates the store instances for you and makes sure they all have the same state.
Moreover it allows to properly handle complex cases like App.getInitialProps
(when using pages/_app
) together with getStaticProps
or getServerSideProps
at individual page level.
Library provides uniform interface no matter in which Next.js lifecycle method you would like to use the Store
.
In Next.js example https://github.com/vercel/next.js/blob/canary/examples/with-redux/store.js#L55 store is being replaced on navigation. Redux will re-render components even with memoized selectors (createSelector
from recompose
) if store
is replaced: https://codesandbox.io/s/redux-store-change-kzs8q, which may affect performance of the app by causing a huge re-render of everything, even what did not change. This library makes sure store
remains the same.
npm install next-redux-wrapper react-redux --save
Note that next-redux-wrapper
requires react-redux
as peer dependency.
Live example: https://codesandbox.io/s/next-redux-wrapper-demo-7n2t5.
All examples are written in TypeScript. If you're using plain JavaScript just omit type declarations. These examples use vanilla Redux, if you're using Redux Toolkit, please refer to dedicated example.
Next.js has several data fetching mechanisms, this library can attach to any of them. But first you have to write some common code.
Please note that your reducer must have the HYDRATE
action handler. HYDRATE
action handler must properly reconciliate the hydrated state on top of the existing state (if any). This behavior was added in version 6 of this library. We'll talk about this special action later.
Create a file named store.ts
:
// store.ts
import {createStore, AnyAction, Store} from 'redux';
import {createWrapper, Context, HYDRATE} from 'next-redux-wrapper';
export interface State {
tick: string;
}
// create your reducer
const reducer = (state: State = {tick: 'init'}, action: AnyAction) => {
switch (action.type) {
case HYDRATE:
// Attention! This will overwrite client state! Real apps should use proper reconciliation.
return {...state, ...action.payload};
case 'TICK':
return {...state, tick: action.payload};
default:
return state;
}
};
// create a makeStore function
const makeStore = (context: Context) => createStore(reducer);
// export an assembled wrapper
export const wrapper = createWrapper<Store<State>>(makeStore, {debug: true});
Same code in JavaScript (without types)
// store.js
import {createStore} from 'redux';
import {createWrapper, HYDRATE} from 'next-redux-wrapper';
// create your reducer
const reducer = (state = {tick: 'init'}, action) => {
switch (action.type) {
case HYDRATE:
return {...state, ...action.payload};
case 'TICK':
return {...state, tick: action.payload};
default:
return state;
}
};
// create a makeStore function
const makeStore = context => createStore(reducer);
// export an assembled wrapper
export const wrapper = createWrapper(makeStore, {debug: true});
It is highly recommended to use pages/_app
to wrap all pages at once, otherwise due to potential race conditions you may get Cannot update component while rendering another component
:
import React, {FC} from 'react';
import {AppProps} from 'next/app';
import {wrapper} from '../components/store';
const WrappedApp: FC<AppProps> = ({Component, pageProps}) => (
<Component {...pageProps} />
);
export default wrapper.withRedux(WrappedApp);
Same code in JavaScript (without types)
import React from 'react';
import {wrapper} from '../components/store';
const MyApp = ({Component, pageProps}) => (
<Component {...pageProps} />
);
export default wrapper.withRedux(MyApp);
getInitialProps
when using class MyApp extends App
which will be picked up by wrapper, so you must not extend App
as you'll be opted out of Automatic Static Optimization: https://err.sh/next.js/opt-out-auto-static-optimization. Just export a regular Functional Component as in the example above.
Each time when pages that have getStaticProps
or getServerSideProps
are opened by user the HYDRATE
action will be dispatched. This may happen during initial page load and during regular page navigation. The payload
of this action will contain the state
at the moment of static generation or server side rendering, so your reducer must merge it with existing client state properly.
Simplest way is to use server and client state separation.
Another way is to use https://github.com/benjamine/jsondiffpatch to analyze diff and apply it properly:
import {HYDRATE} from 'next-redux-wrapper';
// create your reducer
const reducer = (state = {tick: 'init'}, action) => {
switch (action.type) {
case HYDRATE:
const stateDiff = diff(state, action.payload) as any;
const wasBumpedOnClient = stateDiff?.page?.[0]?.endsWith('X'); // or any other criteria
return {
...state,
...action.payload,
page: wasBumpedOnClient ? state.page : action.payload.page, // keep existing state or use hydrated
};
case 'TICK':
return {...state, tick: action.payload};
default:
return state;
}
};
Or like this (from with-redux-wrapper example in Next.js repo):
const reducer = (state, action) => {
if (action.type === HYDRATE) {
const nextState = {
...state, // use previous state
...action.payload, // apply delta from hydration
}
if (state.count) nextState.count = state.count // preserve count value on client side navigation
return nextState
} else {
return combinedReducer(state, action)
}
}
The createWrapper
function accepts makeStore
as its first argument. The makeStore
function should return a new Redux Store
instance each time it's called. No memoization is needed here, it is automatically done inside the wrapper.
createWrapper
also optionally accepts a config object as a second parameter:
debug
(optional, boolean) : enable debug loggingserializeState
anddeserializeState
: custom functions for serializing and deserializing the redux state, see Custom serialization and deserialization.
When makeStore
is invoked it is provided with a Next.js context, which could be NextPageContext
or AppContext
or getStaticProps
or getServerSideProps
context depending on which lifecycle function you will wrap.
Some of those contexts (getServerSideProps
always, and NextPageContext
, AppContext
sometimes if page is rendered on server) can have request and response related properties:
req
(IncomingMessage
)res
(ServerResponse
)
Although it is possible to create server or client specific logic in both makeStore
, I highly recommend that they do not have different behavior. This may cause errors and checksum mismatches which in turn will ruin the whole purpose of server rendering.
This section describes how to attach to getStaticProps lifecycle function.
Let's create a page in pages/pageName.tsx
:
import React from 'react';
import {NextPage} from 'next';
import {useSelector} from 'react-redux';
import {wrapper, State} from '../store';
export const getStaticProps = wrapper.getStaticProps(store =>
({preview}) => {
console.log('2. Page.getStaticProps uses the store to dispatch things');
store.dispatch({type: 'TICK', payload: 'was set in other page ' + preview});
}
);
// you can also use `connect()` instead of hooks
const Page: NextPage = () => {
const {tick} = useSelector<State, State>(state => state);
return (
<div>{tick}</div>
);
};
export default Page;
Same code in JavaScript (without types)
import React from 'react';
import {useSelector} from 'react-redux';
import {wrapper} from '../store';
export const getStaticProps = wrapper.getStaticProps(store =>
({preview}) => {
console.log('2. Page.getStaticProps uses the store to dispatch things');
store.dispatch({type: 'TICK', payload: 'was set in other page ' + preview});
}
);
// you can also use `connect()` instead of hooks
const Page = () => {
const {tick} = useSelector(state => state);
return (
<div>{tick}</div>
);
};
export default Page;
getStaticProps
are opened by user the HYDRATE
action will be dispatched. The payload
of this action will contain the state
at the moment of static generation, it will not have client state, so your reducer must merge it with existing client state properly. More about this in Server and Client State Separation.
Although you can wrap individual pages (and not wrap the pages/_app
) it is not recommended, see last paragraph in usage section.
This section describes how to attach to getServerSideProps lifecycle function.
Let's create a page in pages/pageName.tsx
:
import React from 'react';
import {NextPage} from 'next';
import {connect} from 'react-redux';
import {wrapper, State} from '../store';
export const getServerSideProps = wrapper.getServerSideProps(store =>
({req, res, ...etc}) => {
console.log('2. Page.getServerSideProps uses the store to dispatch things');
store.dispatch({type: 'TICK', payload: 'was set in other page'});
}
);
// Page itself is not connected to Redux Store, it has to render Provider to allow child components to connect to Redux Store
const Page: NextPage<State> = ({tick}) => (
<div>{tick}</div>
);
// you can also use Redux `useSelector` and other hooks instead of `connect()`
export default connect((state: State) => state)(Page);
Same code in JavaScript (without types)
import React from 'react';
import {connect} from 'react-redux';
import {wrapper} from '../store';
export const getServerSideProps = wrapper.getServerSideProps(store =>
({req, res, ...etc}) => {
console.log('2. Page.getServerSideProps uses the store to dispatch things');
store.dispatch({type: 'TICK', payload: 'was set in other page'});
}
);
// Page itself is not connected to Redux Store, it has to render Provider to allow child components to connect to Redux Store
const Page = ({tick}) => (
<div>{tick}</div>
);
// you can also use Redux `useSelector` and other hooks instead of `connect()`
export default connect(state => state)(Page);
getServerSideProps
are opened by user the HYDRATE
action will be dispatched. The payload
of this action will contain the state
at the moment of server side rendering, it will not have client state, so your reducer must merge it with existing client state properly. More about this in Server and Client State Separation.
Although you can wrap individual pages (and not wrap the pages/_app
) it is not recommended, see last paragraph in usage section.
import React, {Component} from 'react';
import {NextPage} from 'next';
import {wrapper, State} from '../store';
// you can also use `connect()` instead of hooks
const Page: NextPage = () => {
const {tick} = useSelector<State, State>(state => state);
return (
<div>{tick}</div>
);
};
Page.getInitialProps = wrapper.getInitialPageProps(store => ({pathname, req, res}) => {
console.log('2. Page.getInitialProps uses the store to dispatch things');
store.dispatch({type: 'TICK', payload: 'was set in error page ' + pathname});
});
export default Page;
Same code in JavaScript (without types)
import React, {Component} from 'react';
import {wrapper} from '../store';
// you can also use `connect()` instead of hooks
const Page = () => {
const {tick} = useSelector(state => state);
return (
<div>{tick}</div>
);
};
Page.getInitialProps = wrapper.getInitialPageProps(store => ({pathname, req, res}) => {
console.log('2. Page.getInitialProps uses the store to dispatch things');
store.dispatch({type: 'TICK', payload: 'was set in error page ' + pathname});
});
export default Page;
Keep in mind that req
and res
may not be available if getInitialProps
is called on client side.
Stateless function component also can be replaced with class:
class Page extends Component {
public static getInitialProps = wrapper.getInitialPageProps(store => () => { ... });
render() {
// stuff
}
}
export default Page;
Although you can wrap individual pages (and not wrap the pages/_app
) it is not recommended, see last paragraph in usage section.
pages/_app
too. But this mode is not compatible with Next.js 9's Auto Partial Static Export feature, see the explanation below.
The wrapper can also be attached to your _app
component (located in /pages
). All other components can use the connect
function of react-redux
.
# pages/_app.tsx
import React from 'react';
import App, {AppInitialProps, AppContext} from 'next/app';
import {wrapper} from '../components/store';
import {State} from '../components/reducer';
// Since you'll be passing more stuff to Page
declare module 'next/dist/next-server/lib/utils' {
export interface NextPageContext {
store: Store<State>;
}
}
class MyApp extends App<AppInitialProps> {
public static getInitialProps = wrapper.getInitialAppProps(store => async ({Component, ctx}) => {
store.dispatch({type: 'TOE', payload: 'was set in _app'});
return {
pageProps: {
// Call page-level getInitialProps
// DON'T FORGET TO PROVIDE STORE TO PAGE
...(Component.getInitialProps ? await Component.getInitialProps({...ctx, store}) : {}),
// Some custom thing for all pages
pathname: ctx.pathname,
},
};
});
public render() {
const {Component, pageProps} = this.props;
return (
<Component {...pageProps} />
);
}
}
export default wrapper.withRedux(MyApp);
Same code in JavaScript (without types)
# pages/_app.tsx
import React from 'react';
import App from 'next/app';
import {wrapper} from '../components/store';
class MyApp extends App {
static getInitialProps = wrapper.getInitialAppProps(store => async ({Component, ctx}) => {
store.dispatch({type: 'TOE', payload: 'was set in _app'});
return {
pageProps: {
// Call page-level getInitialProps
// DON'T FORGET TO PROVIDE STORE TO PAGE
...(Component.getInitialProps ? await Component.getInitialProps({...ctx, store}) : {}),
// Some custom thing for all pages
pathname: ctx.pathname,
},
};
});
render() {
const {Component, pageProps} = this.props;
return (
<Component {...pageProps} />
);
}
}
export default wrapper.withRedux(MyApp);
Then all pages can simply be connected (the example considers page components):
// pages/xxx.tsx
import React from "react";
import {NextPage} from 'next';
import {connect} from "react-redux";
import {NextPageContext} from "next";
import {State} from "../store";
const Page:NextPage<State> = ({foo, custom}) => (
<div>
<div>Prop from Redux {foo}</div>
<div>Prop from getInitialProps {custom}</div>
</div>
);
// No need to wrap pages if App was wrapped
Page.getInitialProps = ({store, pathname, query}: NextPageContext) => {
store.dispatch({type: 'FOO', payload: 'foo'}); // The component can read from the store's state when rendered
return {custom: 'custom'}; // You can pass some custom props to the component from here
}
export default connect((state: State) => state)(Page);
Same code in JavaScript (without types)
// pages/xxx.js
import React from "react";
import {connect} from "react-redux";
const Page = ({foo, custom}) => (
<div>
<div>Prop from Redux {foo}</div>
<div>Prop from getInitialProps {custom}</div>
</div>
);
// No need to wrap pages if App was wrapped
Page.getInitialProps = ({store, pathname, query}) => {
store.dispatch({type: 'FOO', payload: 'foo'}); // The component can read from the store's state when rendered
return {custom: 'custom'}; // You can pass some custom props to the component from here
}
export default connect(state => state)(Page);
You can also use getServerSideProps
or getStaticProps
at page level, in this case HYDRATE
action will be dispatched twice: with state after App.getInitialProps
and then with state after getServerSideProps
or getStaticProps
:
- If you use
getServerSideProps
at page level thenstore
ingetServerSideProps
will be executed afterApp.getInitialProps
and will have state from it, so secondHYDRATE
will have full state from both ⚠️ If you usegetStaticProps
at page level thenstore
ingetStaticProps
will be executed at compile time and will NOT have state fromApp.getInitialProps
because they are executed in different contexts and state cannot be shared. FirstHYDRATE
actions state afterApp.getInitialProps
and second will have state aftergetStaticProps
(even though it was executed earlier in time).
Simplest way to ensure proper merging is to drop initial values from action.payload
:
const reducer = (state: State = {app: 'init', page: 'init'}, action: AnyAction) => {
switch (action.type) {
case HYDRATE:
if (action.payload.app === 'init') delete action.payload.app;
if (action.payload.page === 'init') delete action.payload.page;
return {...state, ...action.payload};
case 'APP':
return {...state, app: action.payload};
case 'PAGE':
return {...state, page: action.payload};
default:
return state;
}
};
Same code in JavaScript (without types)
const reducer = (state = {app: 'init', page: 'init'}, action) => {
switch (action.type) {
case HYDRATE:
if (action.payload.app === 'init') delete action.payload.app;
if (action.payload.page === 'init') delete action.payload.page;
return {...state, ...action.payload};
case 'APP':
return {...state, app: action.payload};
case 'PAGE':
return {...state, page: action.payload};
default:
return state;
}
};
Assume page only dispatches PAGE
action and App only APP
, this makes state merging safe.
More about that in Server and Client state separation.
Using next-redux-wrapper
("the wrapper"), the following things happen on a request:
-
Phase 1:
getInitialProps
/getStaticProps
/getServerSideProps
- The wrapper creates a server-side store (using
makeStore
) with an empty initial state. In doing so it also provides theRequest
andResponse
objects as options tomakeStore
. - In App mode:
- The wrapper calls the
_app
'sgetInitialProps
function and passes the previously created store. - Next.js takes the props returned from the
_app
'sgetInitialProps
method, along with the store's state.
- The wrapper calls the
- In per-page mode:
- The wrapper calls the Page's
getXXXProps
function and passes the previously created store. - Next.js takes the props returned from the Page's
getXXXProps
method, along with the store's state.
- The wrapper calls the Page's
- The wrapper creates a server-side store (using
-
Phase 2: SSR
- The wrapper creates a new store using
makeStore
- The wrapper dispatches
HYDRATE
action with the previous store's state aspayload
- That store is passed as a property to the
_app
orpage
component. - Connected components may alter the store's state, but the modified state will not be transferred to the client.
- The wrapper creates a new store using
-
Phase 3: Client
- The wrapper creates a new store
- The wrapper dispatches
HYDRATE
action with the state from Phase 1 aspayload
- That store is passed as a property to the
_app
orpage
component. - The wrapper persists the store in the client's window object, so it can be restored in case of HMR.
Note: The client's state is not persisted across requests (i.e. Phase 1 always starts with an empty state). Hence, it is reset on page reloads. Consider using Redux persist if you want to persist state between requests.
Since version 7.0
first-class support of @reduxjs/toolkit
has been added.
Full example: https://github.com/kirill-konshin/next-redux-wrapper/blob/master/packages/demo-redux-toolkit.
import {configureStore, createSlice, ThunkAction} from '@reduxjs/toolkit';
import {Action} from 'redux';
import {createWrapper, HYDRATE} from 'next-redux-wrapper';
export const slice = createSlice({
name: 'some',
initialState: {
whatever: null,
},
reducers: {
setWhatever(state, action) {
state.whatever = action.payload;
},
},
extraReducers: {
[HYDRATE]: (state, action) => {
console.log('HYDRATE', state, action.payload);
return {
...state,
...action.payload.some,
};
},
},
});
const makeStore = () =>
configureStore({
reducer: {
[slice.name]: slice.reducer,
}
});
export type AppStore = ReturnType<typeof makeStore>;
export type AppState = ReturnType<AppStore['getState']>;
export type AppThunk<ReturnType = void> = ThunkAction<ReturnType, AppState, unknown, Action>;
export const someAction = (whatever: any): AppThunk => async dispatch => {
dispatch(
subjectSlice.actions.setWhatever({ whatever }),
);
};
export const wrapper = createWrapper<AppStore>(makeStore);
It is recommended to export typed State
and ThunkAction
:
export type AppStore = ReturnType<typeof makeStore>;
export type AppState = ReturnType<AppStore['getState']>;
export type AppThunk<ReturnType = void> = ThunkAction<ReturnType, AppState, unknown, Action>;
Each time when pages that have getStaticProps
or getServerSideProps
are opened by user the HYDRATE
action will be dispatched. The payload
of this action will contain the state
at the moment of static generation or server side rendering, so your reducer must merge it with existing client state properly.
The easiest and most stable way to make sure nothing is accidentally overwritten is to make sure that your reducer applies client side and server side actions to different substates of your state and they never clash:
export interface State {
server: any;
client: any;
}
const reducer = (state: State = {tick: 'init'}, action: AnyAction) => {
switch (action.type) {
case HYDRATE:
return {
...state,
server: {
...state.server,
...action.payload.server
}
}
case 'SERVER_ACTION':
return {
...state,
server: {
...state.server,
tick: action.payload
}
};
case 'CLIENT_ACTION':
return {
...state,
client: {
...state.client,
tick: action.payload
}
};
default:
return state;
}
};
Same code in JavaScript (without types)
const reducer = (state = {tick: 'init'}, action) => {
switch (action.type) {
case HYDRATE:
return {
...state,
server: {
...state.server,
...action.payload.server
}
}
case 'SERVER_ACTION':
return {
...state,
server: {
...state.server,
tick: action.payload
}
};
case 'CLIENT_ACTION':
return {
...state,
client: {
...state.client,
tick: action.payload
}
};
default:
return state;
}
};
If you prefer an isomorphic approach for some (preferably small) portions of your state, you can share them between client and server on server-rendered pages using next-redux-cookie-wrapper, an extension to next-redux-wrapper.
In this case, for selected substates, the server is aware of the client's state (unless in getStaticProps
) and there is no need to separate server and client state.
Also you can use a library like https://github.com/benjamine/jsondiffpatch to analyze diff and apply it properly.
I don't recommend using withRedux
in pages/_document.js
, Next.JS does not provide
a reliable way to determine the sequence when components will be rendered. So per Next.JS recommendation it is better
to have just data-agnostic things in pages/_document
.
Error pages can also be wrapped the same way as any other pages.
Transition to an error page (pages/_error.js
template) will cause pages/_app.js
to be applied but it is always a
full page transition (not HTML5 pushState), so client will have the store created from scratch using state from the server.
So unless you persist the store on the client somehow the resulting previous client state will be ignored.
You can use https://github.com/reduxjs/redux-thunk to dispatch async actions:
function someAsyncAction(id) {
return async function(dispatch, getState) {
return someApiCall(id).then(res => {
dispatch({
type: 'FOO',
payload: res
});
});
}
}
// usage
await store.dispatch(someAsyncAction());
You can also install https://github.com/pburtchaell/redux-promise-middleware in order to dispatch Promises as async actions. Follow the installation guide of the library, then you'll be able to handle it like this:
function someAsyncAction() {
return {
type: 'FOO',
payload: new Promise(resolve => resolve('foo'))
}
}
// usage
await store.dispatch(someAsyncAction());
If you are storing complex types such as Immutable.JS or JSON objects in your state, a custom serialize and deserialize
handler might be handy to serialize the redux state on the server and deserialize it again on the client. To do so,
provide serializeState
and deserializeState
as config options to withRedux
.
The reason is that state snapshot is transferred over the network from server to client as a plain object.
Example of a custom serialization of an Immutable.JS state using json-immutable
:
const {serialize, deserialize} = require('json-immutable');
createWrapper({
serializeState: state => serialize(state),
deserializeState: state => deserialize(state)
});
Same thing using Immutable.JS:
const {fromJS} = require('immutable');
createWrapper({
serializeState: state => state.toJS(),
deserializeState: state => fromJS(state),
});
[Note, this method may be unsafe - make sure you put a lot of thought into handling async sagas correctly. Race conditions happen very easily if you aren't careful.] To utilize Redux Saga, one simply has to make some changes to their makeStore
function. Specifically, redux-saga
needs to be initialized inside this function, rather than outside of it. (I did this at first, and got a nasty error telling me Before running a Saga, you must mount the Saga middleware on the Store using applyMiddleware
). Here is how one accomplishes just that. This is just slightly modified from the setup example at the beginning of the docs. Keep in mind that this setup will opt you out of Automatic Static Optimization: https://err.sh/next.js/opt-out-auto-static-optimization.
Create your root saga as usual, then implement the store creator:
import {createStore, applyMiddleware, Store} from 'redux';
import {createWrapper, Context} from 'next-redux-wrapper';
import createSagaMiddleware, {Task} from 'redux-saga';
import reducer, {State} from './reducer';
import rootSaga from './saga';
export interface SagaStore extends Store {
sagaTask?: Task;
}
export const makeStore = (context: Context) => {
// 1: Create the middleware
const sagaMiddleware = createSagaMiddleware();
// 2: Add an extra parameter for applying middleware:
const store = createStore(reducer, applyMiddleware(sagaMiddleware));
// 3: Run your sagas on server
(store as SagaStore).sagaTask = sagaMiddleware.run(rootSaga);
// 4: now return the store:
return store;
};
export const wrapper = createWrapper<Store<State>>(makeStore, {debug: true});
Same code in JavaScript (without types)
import {createStore, applyMiddleware} from 'redux';
import {createWrapper} from 'next-redux-wrapper';
import createSagaMiddleware from 'redux-saga';
import reducer from './reducer';
import rootSaga from './saga';
export const makeStore = (context) => {
// 1: Create the middleware
const sagaMiddleware = createSagaMiddleware();
// 2: Add an extra parameter for applying middleware:
const store = createStore(reducer, applyMiddleware(sagaMiddleware));
// 3: Run your sagas on server
(store as SagaStore).sagaTask = sagaMiddleware.run(rootSaga);
// 4: now return the store:
return store;
};
export const wrapper = createWrapper(makeStore, {debug: true});
Then in the pages/_app
wait stop saga and wait for it to finish when execution is on server:
import React from 'react';
import App, {AppInitialProps, AppContext} from 'next/app';
import {END} from 'redux-saga';
import {SagaStore, wrapper} from '../components/store';
class WrappedApp extends App<AppInitialProps> {
public static getInitialProps = async ({Component, ctx}: AppContext) => {
// 1. Wait for all page actions to dispatch
const pageProps = {
...(Component.getInitialProps ? await Component.getInitialProps(ctx) : {}),
};
// 2. Stop the saga if on server
if (ctx.req) {
ctx.store.dispatch(END);
await (ctx.store as SagaStore).sagaTask.toPromise();
}
// 3. Return props
return {
pageProps,
};
};
public render() {
const {Component, pageProps} = this.props;
return <Component {...pageProps} />;
}
}
export default wrapper.withRedux(WrappedApp);
Same code in JavaScript (without types)
import React from 'react';
import App from 'next/app';
import {END} from 'redux-saga';
import {SagaStore, wrapper} from '../components/store';
class WrappedApp extends App {
public static getInitialProps = async ({Component, ctx}) => {
// 1. Wait for all page actions to dispatch
const pageProps = {
...(Component.getInitialProps ? await Component.getInitialProps(ctx) : {}),
};
// 2. Stop the saga if on server
if (ctx.req) {
ctx.store.dispatch(END);
await (ctx.store as SagaStore).sagaTask.toPromise();
}
// 3. Return props
return {
pageProps,
};
};
public render() {
const {Component, pageProps} = this.props;
return <Component {...pageProps} />;
}
}
export default wrapper.withRedux(WrappedApp);
In order to use it with getServerSideProps
or getStaticProps
you need to await
for sagas in each page's handler:
export const getServerSideProps = ReduxWrapper.getServerSideProps(
async ({ store, req, res, ...etc }) => {
// regular stuff
store.dispatch(ApplicationSlice.actions.updateConfiguration());
// end the saga
store.dispatch(END);
await store.sagaTask.toPromise();
}
);
If you don't want to opt-out of automatic pre-rendering in your Next.js app, you can manage server-called sagas on a per page basis like the official Next.js "with Redux Saga" example does. If you do go with this option, please ensure that you await any and all sagas within any Next.js page methods. If you miss it on one of pages you'll end up with inconsistent state being sent to client. So, we consider waiting in _app
to be automatically safer, but obviously the main drawback is opting out of automatic static exports.
If you only need to persist small portions of your state, next-redux-cookie-wrapper might be an easy alternative to Redux Persist that supports SSR.
Boilerplate: https://github.com/fazlulkarimweb/with-next-redux-wrapper-redux-persist
Honestly, I think that putting a persistence gate is not necessary because the server can already send some HTML with
some state, so it's better to show it right away and then wait for REHYDRATE
action to happen to show additional
delta coming from persistence storage. That's why we use Server Side Rendering in the first place.
But, for those who actually want to block the UI while rehydration is happening, here is the solution (still hacky though):
// lib/redux.js
import logger from 'redux-logger';
import {applyMiddleware, createStore} from 'redux';
const SET_CLIENT_STATE = 'SET_CLIENT_STATE';
export const reducer = (state, {type, payload}) => {
// Usual stuff with HYDRATE handler
if (type === SET_CLIENT_STATE) {
return {
...state,
fromClient: payload
};
}
return state;
};
const makeConfiguredStore = (reducer) =>
createStore(reducer, undefined, applyMiddleware(logger));
const makeStore = () => {
const isServer = typeof window === 'undefined';
if (isServer) {
return makeConfiguredStore(reducer);
} else {
// we need it only on client side
const {persistStore, persistReducer} = require('redux-persist');
const storage = require('redux-persist/lib/storage').default;
const persistConfig = {
key: 'nextjs',
whitelist: ['fromClient'], // make sure it does not clash with server keys
storage
};
const persistedReducer = persistReducer(persistConfig, reducer);
const store = makeConfiguredStore(persistedReducer);
store.__persistor = persistStore(store); // Nasty hack
return store;
}
};
export const wrapper = createWrapper(makeStore);
export const setClientState = (clientState) => ({
type: SET_CLIENT_STATE,
payload: clientState
});
And then in Next.js _app
page you can use bare context access to get the store (https://react-redux.js.org/api/provider#props):
// pages/_app.tsx
import React from "react";
import App from "next/app";
import {ReactReduxContext} from 'react-redux'
import {wrapper} from "./lib/redux";
import {PersistGate} from 'redux-persist/integration/react';
export default wrapper.withRedux(class MyApp extends App {
render() {
const {Component, pageProps} = this.props;
return (
<ReactReduxContext.Consumer>
{({ store }) => {
<PersistGate persistor={store.__persistor} loading={<div>Loading</div>}>
<Component {...pageProps} />
</PersistGate>
}}
</ReactReduxContext.Consumer>
);
}
});
Or using hooks:
// pages/_app.tsx
import React from "react";
import App from "next/app";
import {useStore} from 'react-redux'
import {wrapper} from "./lib/redux";
import {PersistGate} from 'redux-persist/integration/react';
export default wrapper.withRedux(({Component, pageProps}) => {
const store = useStore();
return (
<PersistGate persistor={store.__persistor} loading={<div>Loading</div>}>
<Component {...pageProps} />
</PersistGate>
);
});
And then in Next.js page:
// pages/index.js
import React from "react";
import {connect} from "react-redux";
export default connect(
(state) => state,
{setClientState}
)(({fromServer, fromClient, setClientState}) => (
<div>
<div>fromServer: {fromServer}</div>
<div>fromClient: {fromClient}</div>
<div><button onClick={e => setClientState('bar')}>Set Client State</button></div>
</div>
));
-
Signature of
createWrapper
has changed: instead ofcreateWrapper<State>
you should usecreateWrapper<Store<State>>
, all types will be automatically inferred fromStore
. -
GetServerSidePropsContext
andGetStaticPropsContext
are no longer exported fromnext-redux-wrapper
, you should useGetServerSideProps
,GetServerSidePropsContext
,GetStaticProps
andGetStaticPropsContext
directly fromnext
. -
All signatures like
({store, req, res, ...}) => { ... }
were changed tostore => ({req, res, ...}) => { ... }
in order to keep Next.js internals free of modifications and for better typings support. -
In version
7.x
you have to manually wrap allgetInitialProps
with proper wrappers:wrapper.getInitialPageProps
andwrapper.getInitialAppProps
. -
window.NEXT_REDUX_WRAPPER_STORE has been removed as it was causing issues with hot reloading
Major change in the way how things are wrapped in version 6.
-
Default export
withRedux
is marked deprecated, you should create a wrapperconst wrapper = createWrapper(makeStore, {debug: true})
and then usewrapper.withRedux(MyApp)
. -
Your
makeStore
function no longer getsinitialState
, it only receives the context:makeStore(context: Context)
. Context could beNextPageContext
orAppContext
orgetStaticProps
orgetServerSideProps
context depending on which lifecycle function you will wrap. Instead, you need to handle theHYDRATE
action in the reducer. Thepayload
of this action will contain thestate
at the moment of static generation or server side rendering, so your reducer must merge it with existing client state properly. -
App
should no longer wrap its children withProvider
, it is now done internally. -
isServer
is not passed incontext
/props
, use your own function or simple checkconst isServer = typeof window === 'undefined'
or!!context.req
or!!context.ctx.req
. -
store
is not passed to wrapped component props. -
WrappedAppProps
was renamed toWrapperProps
.
If your project was using Next.js 5 and Next Redux Wrapper 1.x these instructions will help you to upgrade to 2.x.
-
Upgrade Next.js and Wrapper
$ npm install next@6 --save-dev $ npm install next-redux-wrapper@latest --save
-
Replace all usages of
import withRedux from "next-redux-wrapper";
andwithRedux(...)(WrappedComponent)
in all your pages with plain React Reduxconnect
HOC:import {connect} from "react-redux"; export default connect(...)(WrappedComponent);
You also may have to reformat your wrapper object-based config to simple React Redux config.
-
Create the
pages/_app.js
file with the following minimal code:// pages/_app.js import React from 'react' import {Provider} from 'react-redux'; import App from 'next/app'; import {wrapper} from '../store'; class MyApp extends App { static async getInitialProps({Component, ctx}) { return { pageProps: { // Call page-level getInitialProps ...(Component.getInitialProps ? await Component.getInitialProps(ctx) : {}), } }; } render() { const {Component, pageProps} = this.props; return ( <Component {...pageProps} /> ); } } export default wrapper.withRedux(MyApp);
-
Follow Next.js 6 upgrade instructions for all your components (
props.router
instead ofprops.url
and so on)
That's it. Your project should now work the same as before.