irecord | immutable store that exposes an RxJS | Reactive Programming library

At regular intervals, I want to poll an API that will return an array of records which will almost certainly vary in size. I want each record to display in a CSS animation which takes t amount of time. Therefore, I must buffer the API responses and release them individually, no more frequently than t, so that the animation can complete smoothly.

After much searching and trial and error, I put together this custom RxJS operator (in framework-less TypeScript). However, the double/nested concatMap has a bit of code smell. Is there a more elegant or reactive solution? Are all the inner observables managed properly (unsubscribed from)?

(This is my first custom operator, so any other feedback is welcome.)

I have the following service:

I have a basic Neo4j DB and I'm getting my head around getting data from it into C# under .Net Core. I am using the bolt connection on a 4.03 DB. Windows 10. I may have not grasped Graph Databases yet, but I am trying to build a Person object containing Positions which contain Skill and then Ranks

This code returns 6 instances of Person (A slight concern that I have 6 but thats a minor problem)