@boostmyschool/isomorphic-relay

Isomorphic React Relay [![npm version][npm-badge]][npm]
======================

Enables server-side rendering of React Relay containers.

If you use react-router-relay
you might also become interested in
isomorphic-relay-router.

Acknowledgments
---------------

Thank you to everyone who helped in the development of this project with suggestions,
testing, reported issues, pull-requests. Thank you to the Facebook employees who reviewed
my contributions
to Relay, which helped to improve the server-side rendering support.

Installation
------------

npm install --save @boostmyschool/isomorphic-relay

How to Use
----------

Here is an example with detailed comments of how isomorphic-relay
can be used on the server:
``jsx
import IsomorphicRelay from 'isomorphic-relay';

const rootContainerProps = {
Container: MyContainer,
queryConfig: new MyRoute(),
};

app.get('/', (req, res, next) => {
// Create a Relay network layer. Note that on the server you need to specify
// the absolute URL of your GraphQL server endpoint.
// Here we also pass the user cookies on to the GraphQL server to allow them
// to be used there, e.g. for authentication.
const networkLayer = new Relay.DefaultNetworkLayer(
'http://localhost:8080/graphql',
{ headers: { cookie: req.headers.cookie } },
);

// Use IsomorphicRelay.prepareData() to prefetch the data required for
// rendering of the Relay container.
IsomorphicRelay.prepareData(rootContainerProps, networkLayer).then(({ data, props }) => {
// Use to render your Relay container when the data is ready.
// Note that we cannot use the standard because at the first render
// it renders an empty/loading screen even when all the required data is already available.
// Unlike that, in that case renders normally right at
// the first render, and it is important for server side rendering
// where we do not have a second render.
const reactOutput = ReactDOMServer.renderToString(

);

// To allow the data to be reused in the browser, serialize and embed it
// in the page together with the React markup.
res.render('index.ejs', {
preloadedData: JSON.stringify(data),
reactOutput
});
}).catch(next);
});
`

And here is an example of the code that can be used in the browser:
`jsx
import IsomorphicRelay from 'isomorphic-relay';

const environment = new Relay.Environment();
environment.injectNetworkLayer(new Relay.DefaultNetworkLayer('/graphql'));

// Deserialize the data preloaded on the server.
const data = JSON.parse(document.getElementById('preloadedData').textContent);

// Use IsomorphicRelay.injectPreparedData() to inject the data into the Relay cache,
// so Relay doesn't need to make GraphQL requests to fetch the data.
IsomorphicRelay.injectPreparedData(environment, data);

// Use IsomorphicRelay.prepareInitialRender() to wait until all the required data
// is ready for rendering of the Relay container.
// Note that it is important to use the same rootContainerProps as on the server to
// avoid additional GraphQL requests.
IsomorphicRelay.prepareInitialRender({ ...rootContainerProps, environment }).then(props => {
// Use to render your Relay container when the data is ready.
// Like on the server we cannot use the standard , bacause here
// we also need to render normally right at the initial render, otherwise we would get
// React markup mismatch with the markup prerendered on the server.
ReactDOM.render(, document.getElementById('root'));
});
``

Also see the Star Wars example.

[npm-badge]: https://img.shields.io/npm/v/isomorphic-relay.svg
[npm]: https://www.npmjs.com/package/isomorphic-relay