Spotify web interview (Full stack) What types of questions do they ask?

I have an interview with Spotify coming up, this is the first technical phone screen. I'm assuming data structure algorithm type problems, but I've been surprised in a few interviews to just be asked conceptual javascript questions like why use an arrow function vs regular function etc. (which I didn't prepare for). Anyone with experience in this type of interview know what I should expect? Thanks! #spotify #interview