Ask HN: Build services for compiling iOS apps?

I don't own a Mac computer but am using a cross platform framework which generates XCode project files. Can I pay for an external service to compile these for me and perhaps release them on TestDrive or the App Store? An internet search yields some results, but I'm mainly asking for your experience of possible pitfalls for setting up remote build systems for this platform.

Much like https://unity3d.com/services/cloud-build, except I am using Nativescript, not Unity.