The 777 QRH says: Plan to land ASAP if:-
• only one AC power source remains (main engine generator, APU generator, or backup power system [both generators])
Then there is the Standby Elec system powered by the batteries and a RAT.
The Airbus manual doesn't specify this, indeed the FCOM 3 doesn't contain a LAND ASAP for loss of a Elec gen. If you lose a Gen in flight it only says "consider APU use" I guess Airbus is happy for you to trundle along on only 1 Gen?
it comes down to your judgement on the day considering all factors.
Good luck.