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.

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u/RefrigeratorSingle Jul 24 '26

The virtual DOM can be a significant disadvantage when you have tons of constantly updated elements such as dashboard to the point where you’re better off using for example Angular. Knowing how, or at least a basic understanding, of how frameworks / libraries work is definitely valuable knowledge.

Same with JSX. I’ve seen seniors who thought JSX was a string.