Pop Quiz-style questions are usually found in the first few stages of an interview as the answers are usually short and can possibly be administered by a minimally-technical recruiter.
Pop quiz questions are meant to test how well a candidates understands the theory behind the domain. They can be aced by either having real solid understanding of the concepts or by pure memorization of answers. The questions asked here are pretty limited and most can be found within the next few sections.
- Explain what promises are and what they're useful for.
- Explain the CSS box model.
For more senior candidates, expect to explain more advanced stuff with no absolute answers.
- How does React work? What is Virtual DOM and what problems does it solve?
- Why did you use library X over library Y?
The best and correct way is to prepare for such questions is to really understand the concepts and gets some hands-on experience in applying them in a project. Memorizing the answers is not recommended but is acceptable if you are running out of time.