Block closing/navigating away with unsaved changes

[juliusknorr]

After discussion with @mejo- it could be worth to implement a method in beforeunload to check and block navigating away with unsaved local changes.

Could prevent diverging y.js state and markdown state on the server and also make us aware if there are any saving issues that currently are left unseen.

[juliusknorr]

@mejo- Assigned you as you mentioned you'd be up for looking into that

[juliusknorr]

Might be an interesting read for checking if there are options to still persist on unload: https://www.speedkit.com/blog/unload-beacon-reliability-benchmarking-strategies-for-minimal-data-loss

[juliusknorr]

Another thing I noticed is that when reopening such a document with unsaved changes the autosave would not happen as the frontend does not notice unsaved changes.

Easy steps to reproduce:

• Create a file
• Write something
• Save
• Write something more quickly, wait for a push to happen and force quit your browser tab
• Reopen the file and see that the save indicator is not showing any unsaved changes, but the file content is still the old one

---

This is due to the dirty flag only changing once some more typing is happening

text/src/components/Editor.vue

Line 657 in e67590a

this.dirty = state.dirty

Example file has a last saved version of 128 but the first sync adds more steps:

I think we used to check the saved version against current version but we no longer pass the current version at load time to the frontend:

text/lib/Service/DocumentService.php

Line 125 in 3238541

$stepsVersion = $this->stepMapper->getLatestVersion($document->getId());

Something to think about how we can ensure to still save in such scenarios.