I implemented it for ANTLR (which is LL(*), so not fully recursive descent, but top-down) but never got around to shepherding the patches through.

https://github.com/dberlin/antlr4ts/blob/incremental/Increme... is an intro.

The commits on that branch should give you some idea.

I have regular non-TS ANTLR4 support somewhere too.

I'm happy to chat about it elsewhere as well, drop me a line at my email.