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Server Side Rendering

Server Side Rendering (SSR) can improve the first-load performance of your application. Reactive Data Client takes this one step further by pre-populating the data store. Unlike other SSR methodologies, Reactive Data Client becomes interactive the moment the page is visible, making data mutations instantaneous. Additionally there is no need for additional data fetches that increase server load and slow client hydration, potentially causing application stutters.


App Router

NextJS 14 includes a new way of routing in the '/app' directory. This allows further performance improvements, as well as dynamic and nested routing.

Root Layout

Place DataProvider in your root layout

import { DataProvider } from '@data-client/ssr/nextjs';
import { AsyncBoundary } from '@data-client/react';

export default function RootLayout({ children }) {
return (

Client Components

To keep your data fresh and performant, you can use client components and useSuspense()

'use client';
import { useSuspense } from '@data-client/react';
import { TodoResource } from '../../resources/Todo';

export default function InteractivePage() {
const todos = useSuspense(TodoResource.getList);
return <TodoList todos={todos} />;

Server Components

However, if your data never changes, you can slightly decrease the javascript bundle sent, by using a server component. Simply await the endpoint:

import { TodoResource } from '../../resources/Todo';

export default async function StaticPage() {
const todos = await TodoResource.getList();
return <TodoList todos={todos} />;


More Demos

Class mangling and Entity.key

NextJS will rename classes for production builds. Due to this, it's critical to define Entity.key as its default implementation is based on the class name.

class User extends Entity {
id = '';
username = '';

pk() { return }

static key = 'User';

Pages Router

With NextJS < 14, you might be using the pages router. For this we have Document and NextJS specific wrapper for App

npm install --save @data-client/ssr @data-client/redux redux
import { DataClientDocument } from '@data-client/ssr/nextjs';

export default DataClientDocument;
import { AppCacheProvider } from '@data-client/ssr/nextjs';
import type { AppProps } from 'next/app';

export default function App({ Component, pageProps }: AppProps) {
return (
<Component {...pageProps} />

When fetching from parameters from useRouter(), you will need to add getServerSideProps to avoid NextJS setting router.query to nothing

export default function MyComponent() {
const id: string; = useRouter();
const post = useSuspense(getPost, { id });
// etc
export const getServerSideProps = () => ({ props: {} });

Further customizing Document

To further customize Document, simply extend from the provided document.

Make sure you use super.getInitialProps() instead of Document.getInitialProps() or the Reactive Data Client code won't run!

import { Html, Head, Main, NextScript } from 'next/document';
import { DataClientDocument } from '@data-client/ssr/nextjs';

export default class MyDocument extends DataClientDocument {
static async getInitialProps(ctx) {
const originalRenderPage = ctx.renderPage;

// Run the React rendering logic synchronously
ctx.renderPage = () =>
// Useful for wrapping the whole react tree
enhanceApp: App => App,
// Useful for wrapping in a per-page basis
enhanceComponent: Component => Component,

// Run the parent `getInitialProps`, it now includes the custom `renderPage`
const initialProps = await super.getInitialProps(ctx);

return initialProps;

render() {
return (
<Head />
<Main />
<NextScript />

CSP Nonce

Reactive Data Client Document serializes the store state in a script tag. In case you have Content Security Policy restrictions that require use of a nonce, you can override DataClientDocument.getNonce.

Since there is no standard way of handling nonce in NextJS, this allows you to retrieve any nonce you created in the DocumentContext to use with Reactive Data Client.

import { DataClientDocument } from '@data-client/ssr/nextjs';
import type { DocumentContext } from 'next/document.js';

export default class MyDocument extends DataClientDocument {
static getNonce(ctx: DocumentContext & { res: { nonce?: string } }) {
// this assumes nonce has been added here - customize as you need
return ctx?.res?.nonce;

Express JS SSR

When implementing your own server using express.

npm install --save @data-client/ssr @data-client/redux redux

Server side

import express from 'express';
import { renderToPipeableStream } from 'react-dom/server';
import {
} from '@data-client/ssr';

const rootId = 'react-root';

const app = express();
app.get('/*', (req: any, res: any) => {
const [ServerCacheProvider, useReadyCacheState, controller] =
const ServerDataComponent = createServerDataComponent(useReadyCacheState);

controller.fetch(NeededForPage, { id: 5 });

const { pipe, abort } = renderToPipeableStream(
scripts={[<ServerDataComponent key="server-data" />]}

onCompleteShell() {
// If something errored before we started streaming, we set the error code appropriately.
res.statusCode = didError ? 500 : 200;
res.setHeader('Content-type', 'text/html');
onError(x: any) {
didError = true;
res.statusCode = 500;
// Abandon and switch to client rendering if enough time passes.
// Try lowering this to see the client recover.
setTimeout(abort, 1000);

app.listen(3000, () => {
console.log(`Listening at ${PORT}...`);


import { hydrateRoot } from 'react-dom';
import { awaitInitialData } from '@data-client/ssr';

const rootId = 'react-root';

awaitInitialData().then(initialState => {
<CacheProvider initialState={initialState}>{children}</CacheProvider>,