TypeSocket

TypeScript WebSocket wrapper with disconnection handling and JSON parsing.

Are you a React.js user? You might be interested in the useTypeSocket React hook.

Used in filedrop-web and whiteboard-web.

API is mostly stable. It may change in the future, but the changes shouldn't be breaking.

Installation

TypeSocket is available on npm, you can install it with either npm or yarn:

npm install typesocket
# or:
yarn install typesocket

Example usage

const socket = new TypeSocket<MessageModel>(url, {
  maxRetries: 10,
});

socket.on('connected', () => {
  console.log('connected!');

  socket.send({
    type: 'ping',
  });
});

socket.on('message', (message: MessageModel) => {
  console.log(message.type);
});

socket.on('disconnected', () => {
  console.log('disconnected');
});

socket.connect();

With Redux:

I use TypeSocket with Redux and Redux-Saga like this:

export const socketMiddleware = (url: string) => {
  return (store: MiddlewareAPI<any, any>) => {
    const socket = new TypeSocket<MessageModel>(url);

    socket.on('connected', () =>
      store.dispatch({ type: ActionType.WS_CONNECTED })
    );
    socket.on('disconnected', () =>
      store.dispatch({ type: ActionType.WS_DISCONNECTED })
    );
    socket.on('message', message =>
      store.dispatch({ type: ActionType.WS_MESSAGE, value: message })
    );
    socket.connect();

    return (next: (action: any) => void) => (action: any) => {
      if (
        action.type &&
        action.type === ActionType.WS_SEND_MESSAGE &&
        socket.readyState === 1
      ) {
        socket.send(action.value);
      }

      return next(action);
    };
  };
};

Events

You can attach event listeners to an instance of TypeSocket with .on:

socket.on('message', message => {
  console.log(message);
});

connected

Emitted when a connection gets established.

disconnected

Emitted when the socket is disconnected.

permanentlyDisconnected

Emitted when the socket is permanently disconnected, for example:

• Server gracefully closes the connection.
• Client gracefully closes the connection.
• disconnect is called.
• Retry amount has been exceeded.

message

Emitted when a valid message is received.

The only argument contains an object of type T with a deserialized message.

invalidMessage

Emitted when an invalid message is received.

The only argument contains an object of type string | ArrayBuffer | Blob | ArrayBufferView with a raw message.

rawMessage

Emitted when any message is received.

The only argument contains an object of type string | ArrayBuffer | Blob | ArrayBufferView with a raw message.

API

on(eventType: 'message', listener: (message: T) => void);
on(eventType: 'rawMessage' | 'invalidMessage', listener: (message: string | ArrayBuffer | Blob | ArrayBufferView) => void);
on(eventType: 'connected' | 'disconnected' | 'permanentlyDisconnected', listener: () => void);

off(eventType: 'message', listener: (message: T) => void);
off(eventType: 'rawMessage' | 'invalidMessage', listener: (message: string | ArrayBuffer | Blob | ArrayBufferView) => void);
off(eventType: 'connected' | 'disconnected' | 'permanentlyDisconnected', listener: () => void);

constructor(private url: string, options?: TypeSocketOptions);
connect();
disconnect();
send(data: T);
sendRaw(data: string | ArrayBuffer | Blob | ArrayBufferView);
get readyState();