sentry-javascript: Non-Error exception captured with keys: currentTarget, isTrusted, target, type

FYI, we have just merged a PR that, while not fully addressing the issues outlined here, should at least help a bit with clearing this up: https://github.com/getsentry/sentry-javascript/pull/8374

With this PR, the error messages should at least be clearer. When an Event is captured by captureException, it will better show what kind of event it is, and if it is an ErrorEvent, it will also show the error message.

What this does not address is why sometimes there is no stack track. TBH I am not quite sure why this is happening, as for non-error exception we should be using a syntethic exception to get some stack trace at least. So this remains open for investigation 🤔

Hey. 😉 I was able to debug when this problem occurs. In a situation where “ErrorEvent: ResizeObserver loop limit exceeded” occurs, the event in method “beforeSend” appears as “ErrorEvent: Non-Error exception captured with keys: currentTarget, isTrusted, target, type”. This may lead to a fix for the problem.

Version: 7.51.2

Interestingly, it worked fine in older versions:

Version: 5.30.0

Not sure what is going on here, especially since it’s happening in all browsers.

Basically this occurs because something is running throw event in an event listener, and because this is not being an error thrown we can’t get a stacktrace at all.

Perhaps we should just filter these server side tbh.

Hi @SunStupic thanks for writing in!

Unfortunately, I can’t really tell you either where this error is coming from. You mentioned #6199 already and I also think that this is related. Maybe it is also some script that failed to load. Just that it errored instead of throwing a promise rejection. It’s very hard for us to diagnose these issues without a reproduction. Happy to look into it if there’s a way to reproduce this.

If you you don’t want to see this issue, I suggest you use beforeSend to filter it out:

Sentry.init({
  dsn: 'your_dsn',
  // ...
  beforeSend: (event) => {
    const exception = event.exception?.values && event.exception?.values[0]
    if (exception?.value === 'Non-Error exception captured with keys: currentTarget, isTrusted, target, type') {
      return null;
    }
    return event;
  } 
})

@mydea i’m also tracking the same symptom and we’re on sentry saas. what’s the best way for me to privately share an event link?

I sent you an email (got your email from your website, hope it’s the correct one)!