p2p.js

class Identity {
  constructor(friendlyName) {
    this.clientId = crypto.getRandomValues(new Uint32Array(1))[0];
    this.friendlyName = friendlyName;
  }
}

class PubSubClient {
  constructor(onMessageReceivedCallback) {  
    this.connected = false;
    this.onMessageReceivedCallback = onMessageReceivedCallback;
  }

  async connect(identity, uniqueId) {
    if(this.connected) return;

    this.metadata = { uniqueId: uniqueId, ...identity };

    const ably = new Ably.Realtime.Promise({ authUrl: '/api/createTokenRequest' });
    this.channel = await ably.channels.get(`p2p-sample-${uniqueId}`);

    this.channel.subscribe((message) => {
      this.onMessageReceivedCallback(message.data, this.metadata);
    });

    this.connected = true;
  }

  sendMessage(message, targetClientId) {
    if (!this.connected) { 
      throw "Client is not connected"; 
    }

    message.metadata = this.metadata;
    message.forClientId = targetClientId ? targetClientId : null;
    this.channel.publish({ name: "myMessageName", data: message});
  }
}