react-router-relay

Relay integration for React Router.

This library only supports Relay Classic. For Relay Modern support, see Found Relay.

This library does not support React Router v4, because React Router v4 does not provide the necessary integration points for efficient data fetching with Relay. Additionally, rendering performance will be better with React Router v2 than with React Router v3, as the link subscription logic in React Router v3 triggers unnecessary rerenders with Relay.

Usage

Apply the useRelay router middleware, pass in a Relay environment to <Router>, then define Relay queries and render callbacks for each of your routes:

import { applyRouterMiddleware, /* ... */ } from 'react-router';
import useRelay from 'react-router-relay';

/* ... */

const ViewerQueries = {
  viewer: () => Relay.QL`query { viewer }`
};

const WidgetQueries = {
  widget: () => Relay.QL`query { widget(widgetId: $widgetId) }`
}

ReactDOM.render(
  <Router
    history={history}
    render={applyRouterMiddleware(useRelay)}
    environment={Relay.Store}
  >
    <Route
      path="/"
      component={Application}
      queries={ViewerQueries}
    >
      <Route path="widgets">
        <IndexRoute
          component={WidgetList}
          queries={ViewerQueries}
          prepareParams={prepareWidgetListParams}
        />
        <Route
          path=":widgetId"
          component={Widget}
          queries={WidgetQueries}
          render={({ props }) => props ? <Widget {...props} /> : <Loading />}
        />
      </Route>
    </Route>
  </Router>,
  container
);

react-router-relay will automatically generate a combined Relay query config with all queries and parameters from the active React Router routes, then pass down the query results to each of the route components. As the queries are all gathered onto a single query config, they'll all be fetched in parallel, and the data for your entire page will load and then render in one go.

You can find an example implementation of TodoMVC with routing using react-router-relay at https://github.com/taion/relay-todomvc.

Guide

Installation

$ npm install react react-dom react-relay react-router
$ npm install react-router-relay

Router configuration

Apply the useRelay router middleware, and pass in a Relay environment to the <Router>:

import useRelay from 'react-router-relay';

/* ... */

ReactDOM.render(
  <Router
    history={history}
    routes={routes}
    render={applyRouterMiddleware(useRelay)}
    environment={Relay.Store}
  />,
  container
);

Routes and queries

Basic configuration

For each of your routes that requires data from Relay, define a queries prop on the <Route>. These should be just like the queries on a Relay query config:

const ViewerQueries = {
  viewer: () => Relay.QL`query { viewer }`
};

const applicationRoute = (
  <Route
    path="/"
    component={Application}
    queries={ViewerQueries}
  />
);

Just like with Relay.Renderer, the component will receive the query results as props, in addition to the other injected props from React Router.

If your route doesn't have any dependencies on Relay data, just don't declare queries. The only requirement is that any route that does define queries must have a Relay container as its component.

If your route's Relay data dependencies are a function of the location or of the parameters, you can define a getQueries function on your route that returns the computed queries as a function of the current router state:

<Route
  component={Widget}
  getQueries={({ location, params }) => getWidgetQueries(location, params)}
/>

Path parameters

Any path parameters for routes with queries and their ancestors will be used as parameters on the Relay query config:

const WidgetQueries = {
  widget: () => Relay.QL`
    query {
      widget(widgetId: $widgetId), # $widgetId comes from the path.
    }
  `
}

const Widget = Relay.createContainer(/* ... */, {
  fragments: {
    widget: () => Relay.QL`
      fragment on Widget {
        name,
      }
    `
  }
});

// This handles e.g. /widgets/3.
const widgetRoute = (
  <Route
    path="widgets/:widgetId"
    component={Widget}
    queries={WidgetQueries}
  />
);

Additional parameters

If your queries require additional parameters from the location, such as from the location query or state, you can add those parameters with prepareParams. You can also use prepareParams to do additional conversion or initialization of your parameters.

The prepareParams method has the same signature and behavior as prepareParams on a Relay query config, except that it also receives the current router state as an argument. It is expected to return the same result when given the same previous params and router state.

Additionally, you can use route parameters as variables on your containers:

const WidgetList = Relay.createContainer(/* ... */, {
  initialVariables: {
    color: null,
    size: null,
    limit: null
  },

  fragments: {
    viewer: () => Relay.QL`
      fragment on User {
        widgets(color: $color, size: $size, first: $limit) {
          edges {
            node {
              name,
            },
          },
        },
      }
    `
  }
});

function prepareWidgetListParams(params, { location }) {
  const { color, size } = location.query;
  const limit = location.state && location.state.limit;

  return {
    ...params,
    color,
    size: size && parseInt(size, 10),
    limit: limit || 10,
  };
};

// This handles e.g. /widgets?color=blue&size=3.
const widgetListRoute = (
  <Route
    path="widgets"
    component={WidgetList}
    queries={ViewerQueries}
    prepareParams={prepareWidgetListParams}
  />
);

Named components

For routes with named components, define queries as an object with the queries for each component by name:

<Route
  components={{ foo: FooComponent, bar: BarComponent }}
  queries={{ foo: FooQueries, bar: BarQueries }}
/>

Render callback

You can pass in a custom render callback to your routes:

<Route
  component={WidgetList}
  queries={ViewerQueries}
  render={({ props }) => props ? <WidgetList {...props} /> : <Loading />}
/>

This has the same signature as the render callback on Relay.Renderer, except that, when present, props will also include the injected props from React Router. As on Relay.Renderer, you can return undefined to continuing rendering the last view rendered.

While transitioning, the ready state properties (done, error, retry, stale) will reflect the ready state of the transition as a whole. However, the props object in the render callback for a route will be populated as long as the data for that particular route are ready. For example, if a transition does not change the params to the queries for a parent route, the render callback for that route will have props, even while the render callbacks for its child routes may not.

The argument object to the render callback includes two extra properties: routerProps and element. routerProps contains the props from the router, and unlike props, will be populated regardless of the Relay ready state. routerProps can be used to render child routes while the data for the parent route are still loading, or to otherwise use information from the router to control rendering before the Relay data are available. element contains the base route element without the props from Relay, and can be used to render the route component when the route uses a dynamic component, or when using other router middlewares that may wrap the route component:

({ props, routerProps, element }) => {
  if (!props) {
    return <Loading {...routerProps} />;
  }

  return React.cloneElement(element, props);
}

When using named components, you can define these on a per-component basis, optionally omitting the callback for components that do not need a custom render callback:

<Route
  components={{ foo: FooComponent, bar: BarComponent }}
  queries={{ foo: FooQueries, bar: BarQueries }}
  render={{ foo: renderFoo }}
/>

Additional Relay.Renderer configuration

We pass through additional props on <Router> or the generated router context to the underlying Relay.Renderer. You can use this to control props like forceFetch on the Relay.Renderer:

<Router
  history={history}
  routes={routes}
  render={applyRouterMiddleware(useRelay)}
  forceFetch={true}
  environment={Relay.Store}
/>

Notes

• The default Relay network layer executes each query as a separate network request. If you want to execute all of your queries in a single request, then you will need to use a custom network layer that can send multiple queries in the same request, along with a GraphQL server that can execute multiple queries from a single request.
• react-router-relay uses referential equality on route objects to generate unique names for queries. If your route objects do not maintain referential equality, then you can specify a globally unique name property on the route to identify it.
• Relay's re-rendering optimizations only work when all non-Relay props are scalar. As the props injected by React Router are objects, they disable these re-rendering optimizations. To take maximum advantage of these optimizations, you should make the render methods on your route components as lightweight as possible, and do as much rendering work as possible in child components that only receive scalar and Relay props.

Authors

• @devknoll
• @cpojer
• @taion