I'm an employer. I've interviewed nearly everybody we employ at my company. And treating a hiring interview like a rote memory exam is a terrible way to qualify a potential developer hire!
What do programmers actually do? Try testing that!
We do "whiteboard style" for part of our interviews, but only to cover basic comprehension of algorithms. More than anything, we look for basic familiarity with logic structure, and the demonstrated ability to solve problems. Our coding section of our interview process is in the subject's language of choice, including pseudo code, and is "open book" - we want to see what happens when the dev runs into a problem they don't already know! (Critical test: can they come up with a working, supportable algorithm for a problem they don't yet already know an answer for?)
After 20 years of programming experience, I STILL routinely look up the order of arguments for function calls via Google. Who cares to remember when Google has the answer in 0.10 seconds?
Test what the devs will actually DO in an anticipated normal work day and make your decisions based on that.