The @rhapsody/events package is now available and replaces most use-cases of $rootScope in Angular. The service exposes multiple functions to register, publish, and subscribe to events.
See the Event service README for documentation and examples. See the Messenger entry file for an example of registering events and TopNavMessengerIcon.tsx for an example of both publishing and subscribing to events. See task_mode.es6 for an example of using this in Angular.
The events service is written in Typescript and can be used in JavaScript and Typescript code. New code should use this service and any existing non-Angular code should be refactored to use this service as well. Existing Angular code may need to be refactored as well.