Hello I want to suggest the next idea - in functions like creep.moveTo(target), creep.harvest(target), creep.build(target) etc. make target also string with id.
It's should look like this:
//want this
creep.harvest("5bbcb68ad867df5e54207957")
//instead of
const source = Game.getObjectById("5bbcb68ad867df5e54207957");
creep.harvest(source);