Do you mean "a function that returns the dependencies for a specific (sub) component"?
No, dependency-graph
gives you that
I mean something along these lines:
https://gist.github.com/dball/cd2c0b73df3608459f71428f3c9f90f0
I commonly have this pattern where I have a big complete system, but I sometimes only want to start a subset of it; just the bits necessary to work with one or more high-level components
Ah, gotcha… I tend to have a system creation function for each subsystem, that lists the dependencies, and would let me start just that subsystem — since I use that in the test suite for that subsystem.