React Knowledge Patch
Claude Opus 4.6 knows React through 18.x. It is unaware of the features below, which cover React 19.0 through 19.2 (released 2025-10-01).
Index
| Topic | Reference | Key features |
|---|---|---|
| Server rendering APIs | references/server-rendering.md | cacheSignal, prerender, resume, resumeAndPrerender, Partial Pre-rendering |
<Activity />
New component for pre-rendering and preserving state of hidden UI. Replaces conditional rendering with mode-based visibility.
// Instead of: {isVisible && <Page />}
<Activity mode={isVisible ? 'visible' : 'hidden'}>
<Page />
</Activity>;
Mode behavior
| Mode | Children | Effects | Updates |
|---|---|---|---|
visible |
Shown | Mounted | Processed normally |
hidden |
Hidden | Unmounted | Deferred until React is idle |
When to use
- Pre-rendering likely navigation targets (e.g., next page in a wizard)
- Preserving state on back navigation (e.g., tab content, scroll position)
- Keeping off-screen content ready without the cost of full rendering
Unlike conditional rendering ({show && <Component />}), <Activity> preserves component state and DOM when toggling between modes. Hidden children are deprioritized but not destroyed.
eslint-plugin-react-hooks v6
Now uses ESLint flat config by default.
// eslint.config.js (flat config, v6 default)
import reactHooks from 'eslint-plugin-react-hooks';
export default [
reactHooks.configs.recommended,
];
For legacy .eslintrc config, change the extends name:
- extends: ['plugin:react-hooks/recommended']
+ extends: ['plugin:react-hooks/recommended-legacy']
Reference Files
| File | Contents |
|---|---|
| server-rendering.md | cacheSignal for RSC, Partial Pre-rendering (prerender, resume, resumeAndPrerender), Node stream variants |
Source: Nevaberry/nevaberry-plugins — distributed by TomeVault.