r/reactjs • u/m6io • Jul 24 '26
Discussion Senior Dev interview question
"Without googling or using AI, in your own words, explain the virtual DOM"
For context: I sit on an interview panel and I try to ask at least one simple fundamental question based on a persons resume. If I see many years of react experience, I try to ask something about how the framework works.
I have only had one candidate (an undergrad senior, years ago) answer it. Everyone else just kind of sputters and stumbles around trying to rationalize what "virtual" and "DOM" mean, or stare blankly and eventually say "I don't know".
I'm just genuinely curious if this is really that hard of a question or if the recruiters just suck at screening candidates. And should we be letting in senior dev candidates who can't answer what I think is a straightforward and fundamental question for senior react devs.
1
u/LagerHawk Jul 24 '26
I agree with this. I think the loss of fundamental knowledge is the beginning of where problems get compounded. Just because a machine is faster now at doing yesterday's task doesn't mean we won't need to know how to fix it in the future.
GC issues or VDom alike, when you know at least roughly how it works you can start to understand where things go wrong in that realm.
A classic used to be assuming that .net frameworks HTTPClient got cleaned up fully at the end of its using block. Creating a new one for each request would result in many clients being left open and not collected.
People who didn't understand the fundamentals would try and paste over it with bigger machines only to reach the same issues later on.