Thank you for bringing the issue.
Unfortunately, at this stage we do not have such examples. Nevertheless, this is something that we will definitely consider for the near future.
What I can suggest you, is to check this forum thread
, where a working sample about integrating the BackgroundGeoLocation plugin is provided. As for developing a background service as a whole, I believe there is no plugin that unites the approaches for all the platforms (iOS, Android and WP). Still, you can look at this article about Background Fetch
in order to implement this on iOS. For Android, I would suggest this stackoverflow thread
, where most of the possible plugins are listed.
With the above said, I believe the answer to you second question depends a lot on the requirements of the background service. In other words, the solution can be cross-platform, sharing one code base for basic, or already developed scenarios (like the GeoLocation). Still for more complicated background tasks you may need different code sets.
Finally, this won't require NativeScript, as you should be able to achieve the functionality in hybrid application with the help of custom plugins that utilize the needed native parts.
I hope this helps.