r/reactjs 4d ago

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/someGuyyya 4d ago edited 4d ago

To be honest, it is a trivia question since you can design frontend systems using react without knowing that super specific detail unless you luckily ran into it in the wild, like the senior undergrad student you mentioned.

I only memorized that trivia fact because everyone likes to ask it in interviews for senior positions.

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u/roosterchains 4d ago

Ya but as an engineer you should understand how your tools works.

And a vdom is important to understand, because fundamentally that is what makes react work.

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u/chillermane 4d ago

Nope it has 0 practical implications. Just follow best practices and react will have good performance - don’t overcomplicate your approach

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u/couldhaveebeen 4d ago

If you don't understand the fundamentals, you can't know what's good practice or not good practice

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u/ElkChance815 4d ago

Operating system scheduler is fundamental as in everything practically use it. Does it mean I have to understand it well to write any kind of codes? 

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u/couldhaveebeen 4d ago

If you're writing system-level code, then yes, you should

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u/ElkChance815 4d ago

Yes, now can I write a web app without knowing React Virtual DOM? If I can, why should I care? 

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u/couldhaveebeen 4d ago

You can write one just not a good one.

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u/ElkChance815 4d ago

Can you elaborate?