Tesco interview questions

Made an acount on tesco jobs, then Applied online, got a phone call for an interview, about 5/6 questions face to face, situation based questions asking about prev experience etc.

First round, needed to code a reduce function with unit tests without any help, I passed, but this has nothing to do with actual frontend work, next round I was asked to use diagrams to explain a backend system design, how would I do it, as a frontend developer, a total joke, worst interview interview experience of my life, I cannot take them seriously