On Mobile Safari the fetch process would sometimes fail.

[lhr0909]

Please save me some time and use the following template. In 90% of all issues I can't reproduce the problem because I don't know what exactly you are doing, in which environment, or which y-* version is responsible. Just use the following template even if you think the problem is obvious.

Checklist

• Are you reporting a bug? Use github issues for bug reports and feature requests. For general questions, please use https://discuss.yjs.dev/
• Try to report your issue in the correct repository. Yjs consists of many modules. When in doubt, report it to https://github.com/yjs/yjs/issues/

Describe the bug
I am currently on latest mobile Safari on iOS and the sync process would fail with the following message:

UnknownError: Connection to Indexed Database server lost. Refresh the page to try again

This error is unhandled so it breaks the entire page from loading, since there isn't an error event to subscribe to, it is impossible to catch.

To Reproduce
Steps to reproduce the behavior:

Should be able to see the error on mobile iOS Safari with the simple example and refresh a few times. Going to provide an example.

Expected behavior

in the fetchUpdates function, there should be a callback for handling errors, and the promise chain should have a .catch() block to handle any promise rejections with the error callback. There should be an error event being emitted for the users to handle from the outside.

Screenshots
If applicable, add screenshots to help explain your problem.

Environment Information

• Mobile iOS Safari (version 18.6.1)
• yjs v13.6.27
• y-indexeddb v9.0.12

Additional context
Add any other context about the problem here.

• I'm a sponsor 💖
• This issue is a blocker for my project.

[lhr0909]

Happy to try to come up with a PR if help is needed. Any general direction will be helpful. My app is using Yjs to back the offline-first experience and undo / redo manager for a video subtitle editor on browser! It is the best data solution I have come across for my use case and would love to chime in and help however possible.

[lhr0909]

I removed the blocker checkmark, because there is a bigger issue - Sometimes iOS Safari will block the indexeddb operation without even erroring. I am not sure if this is something that can be caught, but currently as a workaround I put an external timeout to help mitigate the issue. Meanwhile I will try to test on Android Chrome and other mobile browsers to see if there is similar issue.

Regardless, happy to help add an error event if you don't have time. Just let me know!

[lhr0909]

Just found #15 and I think I can pick it up from where he left off.