Is BeforeChange event listener missing in CM6?

I want to listen for changes in codemirror. CM5 used to have a onBeforeChange in react-codemirror2 (which translated to BeforeChange or onChange in CM). This seems to be missing in CM6. The only way to listen for changes I found was to use EditorView.updateListener.of(update => ...)
However this is called after all the extension processing is done like syntax highlighting etc.
In my case, my syntax highlighting info comes after processing most recent changes and thus if I get called after, my most recent character is left out of syntax highlight.

Is there any way to listen for changes before any other extension touches the data (similar to CM5)?

No, there isn’t, at least, not in an imperative way. But I think the underlying problem here is that the way you’re trying to arrange the parsing is just not a very good idea—decoupling the parse state from the editor will cause a whole bunch of problems. Maybe put your parse state in a state field and update it in its update method instead.