The Parinfer core algorithm is mostly "complete", with the remaining work being various editor integrations (which can be quite tricky).

I maintain an up-to-date fork of Parinfer JS here: https://github.com/oakmac/parinfer

The Rust implementation is also popular and actively maintained: https://github.com/eraserhd/parinfer-rust

Both, most editors have their own implementation though, this repo is more a demonstration on the idea around the UX.