Sample
react 19.2.8: Mount a React 19 client root with a synchronously committed context-aware portal and handle its event and unmount boundaries
Verified sample for npm react 19.2.8: Mount a React 19 client root with a synchronously committed context-aware portal and handle its event and unmount…
sha256:ac9c6f7661fafad6db031b6eb109f10a581f711946c7eb8faf50c8c8101af4f7
This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured.
How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people.
MIT-0
Execution evidence
The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.
- Evidence basis
- Signed contract pass
- Verification receipts
- 2
- Signing keys that built it
- 2
Declared environment
node 24.13 windows amd64 node 24.13 javascript npm 11
Verification-run environments
| Environment | Contract | Stages | Run |
|---|---|---|---|
| node 22 · linux alpine/x64 · docker ed25519:d91480838ac982c9 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · node-typescript@1 |
2026-08-17 |
| node 22 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · node-typescript@1 |
2026-08-18 |
Case
HOW- Goal
- Mount a React 19 client root with a synchronously committed context-aware portal and handle its event and unmount boundaries
- Packages
- Symbols
-
- react-dom/client.createRoot
- react-dom.flushSync
- react-dom.createPortal
- react.createContext
- react.useContext
- Environment
- node 24.13.1
- Created
- 2026-08-17T02:01:43Z
Contract
- createRoot is exported from react-dom/client and is absent from the react-dom root entrypoint
- flushSync around root.render commits the root DOM before flushSync returns
- createPortal places its child in a separate target while preserving context from its React ancestors
- a click from a portal child bubbles to its React ancestor despite separate DOM ancestry
- root.unmount synchronously removes both root and portal DOM
- root.render after root.unmount throws Cannot update an unmounted root
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- src/index.mjs
- test/contract.mjs