Questions were more about programming concepts and also technical details. Some questions were not suitable for an interview, I mean you need time for research and study about them.

Applied through a referral. Set up interview and was rejected after 2 weeks. The whole process was a bit clowny though. For a front-end position, you'd normally expect being interviewed by a front-end engineer or something akin to that. However, when they bring you two back-end engineers and a full-stack engineer who explicitly told me they have little to no experience in the technology you're interviewing for, something a bit off.