docs: add how to update values inside arrays

[pooya-badiee]

Related Bug Reports or Discussions

#755

Summary

Add documentation on how to update values inside arrays while avoiding unnecessary re-renders.
I tried to keep it short, let me know if I can add anything

Check List

• pnpm run fix for formatting and linting code and docs

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Project	Deployment	Review	Updated (UTC)
valtio	Ready	Preview, Comment	Jan 11, 2026 0:55am

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[dai-shi]

This looks great to me.
@overthemike Would you like to take a look too?

[pkg-pr-new]

More templates

• counter
• editor-proxyWithHistory
• valtio-photo-booth-demo
• starter

npm i https://pkg.pr.new/valtio@1193

commit: 4802f2a

[overthemike]

This is a fantastic start. I think it might be beneficial to add something at the end that explains why it avoids re-renders. Proxy vs Snapshot is the probably the most difficult to understand for newcomers to library. Maybe something like this?

Because the proxy (in this case: state.items[index]) is a proxy object instead of a snapshot object, accessing it does not track usage. This prevents the parent component from "subscribing" to the item's internal changes, effectively isolating updates to the child component.

[pooya-badiee]

Thank you @overthemike. I implemented the feedback. Since the FAQ answers were too close together, I merged them into a 'Why It Works' section.
Let me know if it makes more sense

[overthemike]

LGTM