As far as combat damage is concerned the FBW takes care of it to keep the aircraft controllable but this would of course only work up to a certain amount of damage. Most of the ideas used for the F-35 have been long proven on the F/A-18 through millions of flight hours including taking damage in combat. A good story comes from early testing on the F-117. An FSD aircraft on test lost one of it's vertical fins and the pilot had no idea until the chase aircraft told him with the FBW compensating automatically.