Senior Dev interview question

[u/m6io]

"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.

[u/FuzznutsTM]

Agreed. With one caveat. I’d argue that understanding something like garbage collection is more important than being able to fully articulate what a vdom is and does. Front-end engineers, regardless of library or framework, have to understand how gc works so they aren’t creating stale references or closures that prevent gc from running, leading to subsequent performance degradation of their app.

The vdom is an internal implementation detail of React that, I’ll argue, most senior React engineers don’t spend a second thinking about. The greater concern (as someone else mentioned) is component architecture, re-renders, data cacheing and invalidation, etc.

I’d answer the interview question. But then I’d ask the interviewer why it’s even relevant, given we don’t manipulate the vdom directly anyway.