A321 pilot reported the flaps failed to extend during arrival. Flight crew diverted and landed safely.

Narrative

During the Arrival phase of landing into ZZZ; FO (First Officer) asked for flaps 1. With that; we incurred a FLT CNTL SLATS FAULT ECAM message. Reviewed Quick Items checklist and performed ECAM procedure. Procedure did not rectify situation and left flats in flaps 1 commanded position. Requested ATC to stay at 8;000' and asked for a vector away from ZZZ. Eventually was put in a holding pattern. FO assumed controls and radio in the holding pattern while Captain continued completing ECAM Procedures; ECAM Follow-ups; advising Flight Attendants and passengers of airport diversion due to an aircraft mechanical condition which required us to land at ZZZ1. FO sent a message to dispatch via ACARS; [advised air traffic control]; and requested from ATC [runway] XXR for landing; safety vehicles standing by; a 20 mile landing final and asked for gate availability in ZZZ1 through Dispatch. Once both Pilots were back together as Pilot Flying and Pilot Not Flying; landing Aassessment was reviewed; non-routine landing procedure was reviewed; approach briefing to RWY XXR was given; a summary of how a No Flap/No Slat Landing will be performed and final checklists were completed. finally; Captain assumed controls for the Approach phase; was given vectors to final approach course and executed landing to RWY XXR. Upon landing; aircraft was met by Safety Vehicles on Taxiway 1. Safety Vehicles accessed condition of Aircraft and after Safety Personnel gave Aircraft all clear message to Flight Crew; Aircraft taxied to the Gate escorted by the Safety Vehicles. Cause: The flaps remained in the flaps retracted position.