Hi Patrick.
I just looked into signalr. Implementation should be pretty straight forward. I would create a wrapper service, that hooks up the signalr stuff with observables.
Typescript is a superset of es2015/6/7, so you can just embed the code you need. Perhaps you need to use some explicit any type so here and there to get rid of some typing issues.
Just make sure you are running in a browser, and make sure your code doesn't get run in any other setting.
Regards
Sander