Safari Desktop: programmatic document.exectCommand('undo') at oncompositionend not working

[michael]

For context: I'm searching for solutions to make my editor (svedit.dev) work with incremental rerendering (after an internal model change). See #13 for details.

I proposed something like this:

function oncompositionend(event) {
  // Roll back the dom changes made throughout the composition, so the DOM is in
  // sync with my document model again, before i apply the change to the document model,
  // allowing for 
  event.resetDOM(); 
  doc.apply(doc.tr.insert_text(event.data);
}

Since an API like event.resetDOM() does not yet exist, I had the idea that programmatically calling undo would have the same effect. And yes, it does. 🍾

function oncompositionend(event) {
  document.execCommand('undo');
  doc.apply(doc.tr.insert_text(event.data);
}

BUT: This does not reliably work on Safari Desktop. 😢 It looks like the Undo is not performed. However, it generally seems to break some internal state of the browser after I run my incremental rerender. Safari Mobile is no problem, as there are no composition events anyways.

To isolate the problem I created a reproduction, where you can see the difference in behavior when running the code in Safari.

[michael]

WAIT: Safari does not have a bug here. The undo didn't happen because Safari correctly yields a onbeforeinput event with eventType 'historyUndo' and in my onbeforeinput handler I had a preventDefault() stopping the undo.

[michael]

Closing in favor of #17