I've got a filter panel in a Vite app on React 18 where the date inputs wipe themselves maybe one time in five when the parent list refetches. I've ruled out the usual cause, the child isn't declared inside the parent's render body, and the key I pass it is a stable string. I put a log in the child's mount effect and it fires every time the fields clear, so it's actually remounting rather than losing state some other way. I've been on this about three hours and I can't work out what's different about the renders where it happens.

I feel like this decision gets made almost by accident on a lot of teams — either everything ends up in Redux/Zustand/Context out of habit, or nothing does and you end up prop-drilling through five components to pass a single boolean. The rule of thumb I've seen most often is "if more than 2-3 components that aren't directly related need it, lift it to global," but that always feels a bit fuzzy in practice. Do you have an actual heuristic you use, or is it more of a gut call that gets refactored later once the pain shows up? Also curious how people handle the in-between case — state that's shared by a meaningful chunk of the tree but is really more "feature-local" than "app-global," where a full global store feels like overkill but prop drilling is annoying.

I kept losing the same explanations in bookmarks and half-remembered blog posts, so I spent a few months writing it all down in one place.

573 topics across 8 sections — the browser, JavaScript, React, Next.js, backend, data, system design, AI/LLM engineering, practices and behavioural.

One rule decided what got in: a topic earns a page if it can plausibly come up in a real interview round, or if you need it to answer something that does. That's why there's no algorithms grind, and why 70 topics are about building with models.

Every page is the same shape — what it is in one line, what it is, why it matters, key points, then the links out. Three to five links per topic, exactly one marked "start here", and a script re-checks all 1,415 on a schedule so they don't rot.

Free, no account, no ads. MIT code, CC-licensed writing, all on GitHub.

Website - https://theengmap.vercel.app

Github - https://github.com/prateekkk26/engineering-map

Product Hunt - https://www.producthunt.com/products/engineering-map?launch=engineering-map

It's on Product Hunt today too if that's your thing — but mainly I'd like to know what's missing, especially from anyone who's run these loops from the other side of the table.

So far, I understand that wrapping a function with startTransition tells React to treat it as a non‑urgent update. So if any urgent action occurs, React can respond to it immediately without blocking.

But here is where I got stuck. The docs say:

“useTransition is a React Hook that lets you render a part of the UI in the background.”

“The function passed to startTransition is called the Action. You can update state and (optionally) perform side effects within an Action, and the work will be done in the background without blocking user interactions.”

I don’t really get what “in the background” really means.

Looking at the example, I don’t understand why, with startTransition, the “Total” only renders once with the final "Total" after clicking “quantity” multiple times, instead of updating multiple times according to the number of times the “quantity” was clicked

Does “run in background” prevent multiple renders and only show the final result??

I've always found translation keys a little strange.

You start with something perfectly readable:

tsx <button>Delete account</button>

Then i18n turns it into something like:

tsx <button>{t("settings.account.delete")}</button>

Now the source code, translation keys, and translation files all have to stay synchronized.

So I tried a different approach with Zintl:

What if the source string itself could be the thing the localization system knows about?

With Zintl, you keep writing normal application code:

tsx <h1>Welcome back</h1> <p>Your account is ready.</p> <button>Continue</button>

Zintl's compiler discovers the localizable strings and builds the localization layer around them.

The goal is that adding i18n shouldn't mean rewriting your application around t() calls.

It's currently alpha, so I'm very much not claiming this is production-ready.

I'm looking for React developers who have actually dealt with i18n to try it and tell me where this approach falls apart.

Especially interested in:

• translation key management
• dynamic/interpolated strings
• component boundaries
• pluralization
• large applications
• translation workflows/TMS
• anything you think a compiler like this should handle

Docs: https://zintljs.github.io/zintl/en

I'd genuinely love the criticism. If you think the whole idea is flawed, tell me why.

I’m reading the React docs, but I find this passage confusing. Could someone explain it to me?

"Another example is reusable state. Concurrent React can remove sections of the UI from the screen, then add them back later while reusing the previous state. For example, when a user tabs away from a screen and back, React should be able to restore the previous screen in the same state it was in before."

React docs link

Hey r/reactjs,

I've been working on Oasis Editor, an open-source TypeScript document editor with its own Canvas-based rendering engine.

React sits on top as an adapter rather than owning the editor runtime, so the same core can be used from vanilla JS, Vue, or headless environments.

The editor handles paged layout, text rendering, selections, images, tables, and document geometry through its own rendering pipeline, and exposes a typed command/plugin API.

Live playground:
https://celsowm.github.io/oasis-editor/#/editor

GitHub:
https://github.com/celsowm/oasis-editor

I'd love feedback on the React integration, API design, and overall architectu

I want in my practice chat app to be able to paste an image into a text input and be able to send it, on how to actually do this, I am unsure

My idea is this given a text input:

- a user could Ctrl-V (i.e., paste) something from his clipboard (a file in this instance), until a download url is returned (see below) there will be some loader spinner thingy
- In the backend is requested an Upload URL
- (somehow) whatever they pasted is immediately uploaded, likely by the path? But I am still a little bit unsure on that part
- a Download URL is returned on that S3 upload (SOMEHOW)
And thus you replace that temporary spinner with the download URL and the person can send it.

This is at least my idea on how you should be able to upload a piece of media in a message and be able to send it, I don't want just message attachments, that would be an easier story because once the association is made between the message and attachment you display it. I want something like in forums where the image can be embedded anywhere,

There is also one more small concern, on slow connection do you want to wait for the file to finish uploading first and then allow the user to send their message, or just send the message and let the upload come later, if the latter, how would you go across with doing that!?

The issue is, I have no idea on how to do this, I gave my approach above, I would really appreciate it if you guys gave some advice on what your approach would be and secondly, how to implement it, I already can get a presigned URL so that's not an issue

This is more of a design question, but it's also really interlinked with react so sorry if this is the wrong place to ask! ;-;

That's all :)

I recently wrote a blog post on how we can improve our static analysis using linting, custom rules, and hooks, all using oxlint.

It's quite a big article btw.

https://saybackend.com/blog/lint-ai-generated-code/