React Query `useSubscription` hook

Background

While React Query is very feature rich, it misses one thing - support for streams, event emitters, WebSockets etc. This library leverages React Query's useQuery to provide useSubscription hook for subscribing to real-time data.

General enough solution

React Query useQuery's query function is any function which returns a Promise. Similarly, useSubscription's subscription function is any function which returns an Observable.

Installation

NPM

npm install react-query-subscription react react-query@3 rxjs@7

yarn add react-query-subscription react react-query@3 rxjs@7

Use cases

Subscribe to WebSocket

TODO

Subscribe to Event source

import { QueryClientProvider, QueryClient } from 'react-query';
import { ReactQueryDevtools } from 'react-query/devtools';
import { useSubscription, eventSource$ } from 'react-query-subscription';

const queryClient = new QueryClient();

function App() {
  return (
    <QueryClientProvider client={queryClient}>
      <SseExample />
      <ReactQueryDevtools initialIsOpen={false} />
    </QueryClientProvider>
  );
}

function SseExample() {
  const { data, isLoading, isError, error } = useSubscription(
    'some-key',
    () => eventSource$('/api/v1/sse'),
    {
      // options
    }
  );

  if (isLoading) {
    return <div>Loading...</div>;
  }
  if (isError) {
    return (
      <div role="alert">
        {error?.message || 'Unknown error'}
      </div>
    );
  }
  return <div>Data: {JSON.stringify(data)}</div>;
}

GraphQL subscription using `graphql-ws`

import { QueryClientProvider, QueryClient } from 'react-query';
import { ReactQueryDevtools } from 'react-query/devtools';
import { useSubscription } from 'react-query-subscription';
import { Observable } from 'rxjs';
import { createClient } from 'graphql-ws';
import type { Client, SubscribePayload } from 'graphql-ws';

const queryClient = new QueryClient();

function App() {
  return (
    <QueryClientProvider client={queryClient}>
      <GraphQlWsExample postId="abc123" />
      <ReactQueryDevtools initialIsOpen={false} />
    </QueryClientProvider>
  );
}

const client = createClient({ url: 'wss://example.com/graphql' });

/**
 * @see https://github.com/enisdenjo/graphql-ws#observable
 */
export function fromWsClientSubscription<TData = Record<string, unknown>>(
  client: Client,
  payload: SubscribePayload
) {
  return new Observable<TData | null>((observer) =>
    client.subscribe<TData>(payload, {
      next: (data) => observer.next(data.data),
      error: (err) => observer.error(err),
      complete: () => observer.complete(),
    })
  );
}

interface Props {
  postId: string;
}

interface Comment {
  id: string;
  content: string;
}

function GraphQlWsExample({ postId }: Props) {
  const { data, isLoading, isError, error } = useSubscription(
    'some-key',
    () => fromWsClientSubscription<{ comments: Array<Comment> }>({
      query: `
        subscription Comments($postId: ID!) {
          comments(postId: $postId) {
            id
            content
          }
        }
      `,
      variables: {
        postId,
      },
    }),
    {
      // options
    }
  );

  if (isLoading) {
    return <div>Loading...</div>;
  }
  if (isError) {
    return (
      <div role="alert">
        {error?.message || 'Unknown error'}
      </div>
    );
  }
  return <div>Data: {JSON.stringify(data?.comments)}</div>;
}