v1.1.2 or later can crash apps on Opera Mini extreme data saving mode

[jroebu14]

Hi,

We first reported a problem with v1.1.2 here #159 which we submitted a fix for.

However when we upgraded to v2.0.1, which contains the fix, we discovered the crash still happened on Opera Mini.

To mitigate this we resorted to wrapping the performance metrics collection functions in a try/catch and logged out the error. This is the error we see - Undefined variable: performance.

It seems the Performance API is not supported at all in Opera Mini extreme data saving mode - https://caniuse.com/?search=performance

We get a moderate amount of traffic on this browser so it would be great if we could help expand support to this browser again. If supporting this browser is too tricky then consumers should be aware that they may have to handle errors coming from this package if they need to serve an audience that use Opera Mini.

Happy to help with this issue.

Thanks!

[philipwalton]

Hmmm, I'm happy to add reasonable checks to avoid errors, but I can't actually reproduce this myself.

I've downloaded Opera Mini and turned on extreme data saver mode and I still see the global performance object. (Testing on OPR/60.0.2254.59405).

Do you know what version of Opera Mini you're seeing the error in?

[philipwalton]

Update: after a bit more testing I discovered that I was seeing the global performance object only when testing a page on localhost (well, actually 192.168.X.X). When I tried loading the same page via a public web address, then I saw that indeed:

typeof performance === "undefined" // true

I'll publish a fix for this.

[philipwalton]

The fix for this should be live in v2.1.1.

[jroebu14]

Brilliant! Thanks for this!

The fact that you didn't see the error on localhost may be because Opera Mini uses a transcoding proxy server to retrieve light versions of websites. If you are testing on localhost then I don't think requests would go through the proxy server because it wouldn't be able to access anything on your local machine or network.

This explains in more detail https://maqentaer.com/devopera-static-backup/http/dev.opera.com/articles/view/opera-mini-and-javascript/index.html