Web Worker error notifying

Right now you can technically catch errors from Workers by listening to it’s onerror event. However it seems (at a first glance) that the stacktrace is lost. It might be worth having an additional (tiny) script to import within a worker which basically proxies the error & stacktrace back to the main thread for it to notify (making the worker completely config-less).

I still have to see what’s technically possible, but I’m pretty confident it can be done.

Thoughts?

[kattrali]

Thanks for the report, @jacobmarshall. Seems like kinda of a hairy issue, but I’m open to ideas. 🤔 @eanakashima @wordofchristian might also have some thoughts.

[JacobEvelyn]

For anyone here who saw @jmshal’s statement

Right now you can technically catch errors from Workers by listening to its onerror event.

and is wondering how to actually do that, I dug through the code for a while and eventually came up with this:

worker.onerror = function(errorEvent) {
  const bugsnagReport = new bugsnagClient.BugsnagReport(
    "worker.onerror",
    errorEvent.message,
    [
      {
        fileName: errorEvent.filename,
        lineNumber: errorEvent.lineno,
        columnNumber: errorEvent.colno
      }
    ],
    {
      severity: "error",
      unhandled: true,
      severityReason: { type: "unhandledException" }
    }
  );

  bugsnagClient.notify(bugsnagReport);
};

Since the ErrorEvent interface is used for every error event except for window.onerror, I wonder if it makes sense to allow Bugsnag.notify to take an ErrorEvent and just change Bugsnag’s window.onerror (which does not pass an ErrorEvent—see MDN doc) to window.addEventListener("error", ...) (which does). Thoughts?