How to implement async event tracking in JS runtime without blocking RPC response?

Runtime Framework
1

I’m currently using the JavaScript runtime in Nakama , and I want to implement event tracking (e.g., sending to Mixpanel) when a custom RPC is called. However, I want to return the RPC response immediately to the client and send the tracking event asynchronously in the background , without blocking the response.

I understand that the JS runtime does not allow us to register custom event handlers for nk.event(…). So I was thinking of the following workaround — could you please confirm if this approach is correct or suggest a better one?

Proposed Flow:

  1. In the JS custom RPC, I call:
nk.event({
  name: "analytic_event",
  properties: { action: "purchase", userId: ctx.userId },
  userId: ctx.userId,
  timestamp: Date.now(),
});
  1. This RPC returns immediately to the client.
  2. On the Go runtime side, I register a handler for this custom event (analytic_event), and inside it, I call external services like Mixpanel to track the event.

Questions:

  • Is this pattern valid?
  • Can Go runtime subscribe to events created by JS runtime using nk.event()?
  • Is there a more elegant way to achieve async side effects after an RPC call in JS? (return rpc response to client fast and do some action after return to client)

Thanks

2

base on this discussion:

3

ChatGPT give some suggestions something like

setTimeout(() => {
  nk.rpc("track_analytic_event", JSON.stringify({
    action: "purchase",
    userId: ctx.userId
  }));
}, 0);

Does this code work?

4

Yes, this pattern is valid.

The Go runtime can subscribe to events created by the JS runtime using nk.event. That’s currently the only way to do it as far as I know. We do exactly this for sending events to Mixpanel asynchronously.