How to select a single idle fabber on the current planet in focus

Hello,
I am trying to select a single idle fabber on the current planet in focus, in live_game:

//get planetId from current primary camera
var planetId = model.cameraFocus.primary().planetId();

//how do I select one idle fabber? api.select does not seem to have any such function.

Would you be after a specific idle fabber? Or just any random one among several available?

As a user you can hit your "select all idle fabbers" hotkey then use the "Keybind extensions" mod to select just 1 item from the current selection (that's one out of the many great features of this mod).
So, as a modder, you could find your answer by looking at the "Keybind extensions" code.