Use socket.io v3 with React, in hooks (React v16.8+).

If you want to use socket.io in v2, you might want to use the v2.0.4 of this package. The last commit related to the v2 version is this one.

Usage

Installation

$ yarn add use-socketio

In your code

useSocket hook

Listen to a specific event and trigger the according callback every time there's one. This hooks doesn't trigger a re-render. You have to manage it yourself.

import { SocketIOProvider, useSocket } from "use-socketio";

const Twitter = () => {
  const [tweets, setTweet] = useState([]);

  const { socket, subscribe, unsubscribe } = useSocket("tweet", (newTweet) =>
    setTweet([newTweet, ...tweets])
  );

  return tweets.length ? (
    <ul>
      {tweets.map((tweet) => (
        <li key={tweet.id}>{tweet.text}</li>
      ))}
    </ul>
  ) : (
    <p>Actually waiting for the websocket server...</p>
  );
};

const App = () => (
  <SocketIOProvider url="http://localhost:3000" opts={socketIoOptions}>
    <Twitter />
  </SocketIOProvider>
);

The socketio options to pass to the provider are available here: https://socket.io/docs/client-api/#new-Manager-url-options.

useLastMessage hook

Listen to the latest message received on a specific event name. This hook triggers a re-render so you don't have to.

import { SocketIOProvider, useLastMessage } from "use-socketio";

const Twitter = () => {
  const { data: lastMessage, socket, subscribe, unsubscribe } = useLastMessage(
    "tweet"
  );

  return <p>{lastMessage || "Waiting for some tweets"}</p>;
};

const App = () => (
  <SocketIOProvider url="http://localhost:3000">
    <Twitter />
  </SocketIOProvider>
);

Notes

For example on how to implement a Socket.io server, you can take a look at the socket.io the example folder.