CodeSampleX

Sample

react 18.3.1: startTransition executes its callback synchronously, returns undefined, and scopes the transition batch config exclusively to synchronous execution.

Verified sample for npm react 18.3.1: startTransition executes its callback synchronously, returns undefined, and scopes the transition batch config…

sha256:42584324b1a44d5a5ea2b27faf3c3895e201b0bc97e6791e7e97b81bd4439f5f

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 linux x64 node node npm

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
startTransition executes its callback synchronously, returns undefined, and scopes the transition batch config exclusively to synchronous execution.
Packages
Symbols
  • react.startTransition
Environment
node
Created
2026-08-17T06:44:11Z

Contract

  1. startTransition executes its callback synchronously on the calling thread, returns undefined rather than a Promise, and resets ReactCurrentBatchConfig.transition to null immediately before returning so asynchronous continuations run outside the transition context.
  2. startTransition returns undefined even when the callback returns a Promise or value
  3. ReactCurrentBatchConfig.transition is an active object during synchronous callback execution and is restored to null upon return
  4. asynchronous work scheduled inside startTransition executes after the transition context has already been reset to null
  5. synchronous errors thrown inside startTransition propagate immediately while reliably restoring the previous transition context
  6. nested startTransition calls maintain and restore the enclosing transition batch configuration

Files

  • NOTES.md
  • csx.json
  • package-lock.json
  • package.json
  • test/contract.mjs

Download the source artifact (tar.gz)

Origin Seeder

csx-seed