What is the best way to modify text on a text-change event in Quill?

We’re trying to build track changes into Quill, which includes checking for user input, and then modifying the document. For example, if a user deletes some text, we reverse the deletion, and then apply a track-deletion attribute. Here is a simplified example of what we do:

quill.on('text-change', (delta, oldContents, source) => {
  if (source !== 'user') return;

  const trackChangesDelta = delta.invert(oldContents);

  trackChangesDelta.ops.forEach((op) => {
    if (op.insert) op.attributes['track-deletion'] = true;
    // Also handle tracked insertions, etc...
  });

  quill.updateContents(trackChangesDelta);
});

This approach mostly works, but runs into some slightly odd cases:

• If I have the text foo, and I highlight the text, and then type the letter o, I’d expect the entire word to be deleted, followed by an o insertion. Instead, Parchment appears to “optimise” the op, and instead do a pair of deletions either side of the middle o

• If I highlight and replace text at the start of a paragraph, then the inserted letter goes to the end of the deletion, but my cursor stays in the wrong place

I think both of these issues are symptoms of the fact that we’re performing a text-change within a text-change, and I was wondering if there was a better (more synchronous?) way of hooking into the Quill document life-cycle.

For example, the second issue we have is resolved by using a setTimeout to let the Quill document finish processing the text-change before we apply our track changes, but that then results in some other jittery behaviour.

Ideally, I’d like to catch the text-change before it’s even been applied to the document, but as far as I can tell, neither Quill nor Parchment offers a suitable hook?