Knowing the difference between async and sync is relevant to any JavaScript developer's daily tasks. If you are hiring a JavaScript developer it's 100% a fair question to ask. If you are hiring a generalist maybe not, but if they have JavaScript experience in the last 3 years listed on their resume, I again say it's fair to ask.
Asking about async/sync in JS is completely different from asking someone what obscure features like finalizers are in Java. One is used on an hourly basis when writing code, the other one is never used except in obscure legacy code.
If you do what you're proposing and just ask about projects I think you'll find it's easy for incompetent people who are floundering around and copy pasting from stackoverflow without understanding what they're copying to pass your bar. I copy from stack overflow all the time but I understand what I'm copying and why it works and when it doesn't work.
Asking about async/sync in JS is completely different from asking someone what obscure features like finalizers are in Java. One is used on an hourly basis when writing code, the other one is never used except in obscure legacy code.
If you do what you're proposing and just ask about projects I think you'll find it's easy for incompetent people who are floundering around and copy pasting from stackoverflow without understanding what they're copying to pass your bar. I copy from stack overflow all the time but I understand what I'm copying and why it works and when it doesn't work.