Local offline development with Firestore

Is there any way to use the gcloud firestore emulator to do local offline development when using the web client SDK? (ie client-side JS).

I've found both

firebase serve --only firestore and gcloud beta emulators firestore start

but not sure of intended use cases of either, as the documentation doesn't give much to go on?

Can firestore be used offline?

When you initialize Firestore, you can enable or disable offline persistence: For Android and Apple platforms, offline persistence is enabled by default.

Can Firebase be used locally?

The Firebase Local Emulator Suite is a set of advanced tools for developers looking to build and test apps locally using Cloud Firestore, Realtime Database, Cloud Storage, Authentication, Cloud Functions, Pub/Sub, Firebase Hosting and Firebase Extensions.

Does Firebase storage work offline?

Firebase has great option of using their database and sending data to their db even if you are offline, and then when the connection is up again, it sends automatically the data to the db.

The emulator functionality has improved significantly since I posted this question. The documentation is here now: https://firebase.google.com/docs/emulator-suite