websocket

websocket.js

class Socket {
  constructor(
    domain,
    { reconnection = true, reconnectionDelay = 1000 } = {
      reconnection: true,
      reconnectionDelay: 1000,
    }
  ) {
    this.ws = this.connect(domain);
    this.reconnection = reconnection;
    this.reconnectionDelay = reconnectionDelay;
    this.CLOSED = true;
    this.events = {};
  }

  connect(domain) {
    if (!domain) return null;

    this.ws = new WebSocket(domain);
    this.CLOSED = false;

    this.ws.onopen = () => {
      if (this.events.open) this.events.open();
      // subscribe to some channels
      this.ws.send(JSON.stringify({
        //.... some message the I must send when I connect ....
      }));
    };

    this.ws.onmessage = (e) => {
      const type = e.data && e.data.type;
      const data = e.data && e.data.data;

      if (this.events[type]) this.events[type](JSON.parse(data));
    };

    this.ws.onclose = (e) => {
      console.log('Socket is closed. Reconnect will be attempted.', e.reason);

      if (this.reconnection && !this.CLOSED) {
        setTimeout(() => {
          this.ws = this.connect(domain);
        }, this.reconnectionDelay);
      }
    };

    this.ws.onerror = (err) => {
      console.error(
        'Socket encountered error: ',
        err.message,
        'Closing socket'
      );
      this.ws.close();
    };

    return this.ws;
  }

  disconnect() {
    this.CLOSED = true;
    this.ws.close();
  }

  on(eventName, handler) {
    this.events[eventName] = handler;
  }

  emit(eventName, data) {
    this.ws.send(
      JSON.stringify({
        type: eventName,
        data,
      })
    );
  }
}

const ws = new Socket(domain, options);

// Emits an event to the socket identified by the string name.
// ws.emit('hello', 'world');

// Register a new handler for the given event.
// ws.on('news', (data) => { console.log(data); });