Firefox old versions - throw an empty/unknown list of entryTypes

[Zizzamia]

There is this old issue related to using PerformanceObserver with entryTypes 'paint' in Firefox v58: https://bugzilla.mozilla.org/show_bug.cgi?id=1403027 .

It is not a problem anymore, I think was fixed with v63. In case the library is looking to support older versions of Firefox, I found it could be convenient to wrap the PerformanceObserver in a try/catch for getFCP.

I can open a PR for it, but I thought to double-check first if you were interested in such a fix.

[philipwalton]

Thanks. I wasn't aware of that bug, though from looking at the code, I already do put that check in a try/catch block, so I think it should be ok, no?

[Zizzamia]

Oh, I miss that. Yeah, we should be good! I'm going to close this issue.
More an open question, should the library expose any error caught, maybe with an onError listener that devs can use to connect Bugsnag or their favorite bug report tool?

[philipwalton]

More an open question, should the library expose any error caught, maybe with an onError listener that devs can use to connect Bugsnag or their favorite bug report tool?

Hmmm, I don't think we'd want to report errors for expected failures (e.g. a browser just not supporting the API), and other than that I'd assume developers wanting to catch errors would just use try/catch or standard uncaught error handling mechanisms?