User Notifications

let accessToken = initialAccessToken;
let lastEventId: string | undefined;
const seen = new Set<string>();

function connect(attempt = 0) {
  const ws = new WebSocket(`wss://ws.agg.market/ws?appId=${appId}`);

  const authenticate = () =>
    ws.send(JSON.stringify({ action: "authenticate", token: accessToken, resumeFrom: lastEventId }));

  ws.onmessage = async (frame) => {
    const msg = JSON.parse(frame.data);
    switch (msg.type) {
      case "connected":
        attempt = 0;
        authenticate();
        return;
      case "auth_expiring":
      case "auth_expired":
        try {
          accessToken = await client.refreshAccessToken();
          authenticate();
        } catch {
          await client.signOut();
          ws.close();
        }
        return;
      case "resumed":
        if (!msg.complete) await seedFromRest(); // some events may be missing
        return;
    }
    if (msg.eventId) {
      if (seen.has(msg.eventId)) return; // a resume can resend events you have
      seen.add(msg.eventId);
      lastEventId = msg.eventId;
    }
    applyUserEvent(msg);
  };

  ws.onclose = (event) => {
    if (event.code === 4001 || event.code === 4003) return; // configuration error
    const delay = Math.min(1000 * 2 ** attempt, 30_000) * (0.5 + Math.random() / 2);
    setTimeout(() => connect(attempt + 1), delay);
  };
}

await seedFromRest();
connect();