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React 19.2 is now available! This release includes Activity, useEffectEvent, React Performance Tracks, partial pre-rendering, and more: react.dev/blog/2025/10...

<Activity> lets you break your app into “activities” that can be controlled and prioritized. It ships with 2 modes: "hidden" and "visible". When "hidden", Activity hides the children, unmounts effects, and defers all updates until React has nothing left to work on. react.dev/reference/re...

Performance Tracks are a new set of custom tracks in performance profiles that show more info about your React app. They include a Scheduler track that shows the priority of what React is working on, and a Components track to show which component is being worked on. react.dev/reference/de...

Partial pre-rendering is a new capability in React DOM that lets you pre-render part of your app ahead of time, and then resume rendering later to fill in the remaining content. Support includes new APIs to resume from the existing prerender APIs: react.dev/blog/2025/10...

We also released v6 of eslint-plugin-react-hooks. This release includes eslint flat config by default, and lets you opt-in to a new set of lint rules powered by the React Compiler. In a future release, we plan to add these new lint rules to the recommended preset: react.dev/reference/es...

I found some of the limitations put on this a little unexpected, especially the requirement to not pass the callback in props into other components. Well the last time I needed something like useEffectEvent, these limitations would've been no issue, but I wonder if that will generally be the case.

conceptually an Effect Event is like a block of code inside an Effect, kind of like event { … } the API is a bit of like writing the compiled output for that

the API is powerful because it completely turns off reactivity for the code inside. however, that’s also very dangerous if used all over the place because you don’t know where along the chain reactivity might disappear. the constraints prevent that

🐛 the playground is using an older version of React and shows: Error (0, _react.useEffectEvent) is not a function. (In '(0,