$ npm install level-promise
At the application level, promises vs callbacks is yours to choose. If you use this in a LevelUp extension that isn't explicitly about promises, I will find you and I will destroy you. Play nice with the rest, use callbacks for your extension. If your extension works with level-manifest, it'll work with this.
LevelPromise.install(db), if that suits your tastes) and you're off!
Every method marked as async by level-manifest will now return a promise when you don't pass it a callback.
It recurses into sublevels.