This example demonstrates how to build a nested hierarchy from a streaming datasource.
Groups in the hierarchy are generated and sorted “on demand” as they are pulled from the data$ Observable.
Rx.Observable.groupBy() produces GroupedObservables which are scanned into arrays and then combined using flatMapLatest(Rx.Observable.combineLatest).
(Note: It’s important to shareReplay the GroupedObservables)
This example also uses babel-standalone to enable in-browser ES6 features.