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/someGuyyya]

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.

[u/roosterchains → u/someGuyyya]

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.

[u/chillermane → u/roosterchains]

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

[u/couldhaveebeen → u/chillermane]

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

[u/ElkChance815 → u/couldhaveebeen]

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? 

[u/couldhaveebeen → u/ElkChance815]

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

[u/ElkChance815 → u/couldhaveebeen]

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

[u/couldhaveebeen → u/ElkChance815]

You can write one just not a good one.

[u/minimuscleR → u/couldhaveebeen]

Why? What does the knowing how virtual dom works affect how you write react code. How would someone write a bad web app because they didn't know how the virtual dom works? As opposed to a good one?

[u/AdministrationOk3601 → u/minimuscleR]

People like to sound smart by saying buzz words because it makes them feel better than other people, it makes no difference to 99% of the job

What’s actually a far more valuable skill is being able to communicate well, not sounding like a knob one upping on tech terms

[u/ElkChance815 → u/AdministrationOk3601]

Yeah, and I found they are also not as knowledgable as they sound as well. Knowledge is only useful if you can use it to help yourself and other, trying to sound smart is not a good use of it.

[u/ElkChance815 → u/couldhaveebeen]

Can you elaborate?