Sample
react 19.0.0: Handle React.Children key rewriting, Fragment opacity, null return shapes in map, and cloneElement key string coercion traps in React
Verified sample for npm react 19.0.0: Handle React.Children key rewriting, Fragment opacity, null return shapes in map, and cloneElement key string coercion…
sha256:40432561f0a52d20a9a1ac819998ffd8ede83d0436787b49bcf7949a41cf71a9
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 |
2026-08-16 |
| 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
- Handle React.Children key rewriting, Fragment opacity, null return shapes in map, and cloneElement key string coercion traps in React
- Packages
- Symbols
-
- react.Children.toArray
- react.Children.map
- react.Children.only
- react.Children.count
- react.cloneElement
- Environment
- node
- Created
- 2026-08-16T07:54:04Z
Contract
- assert React.Children.toArray rewrites user keys with '.$' prefix, assigns '.0' to unkeyed items, and recursively flattens nested arrays with index prefixes
- assert React.Children.toArray and Children.count treat React.Fragment as a single opaque element without unwrapping its children
- assert React.Children.toArray filters out null, undefined, and booleans while strictly preserving numeric 0 and empty string
- assert React.Children.map returns null or undefined on null or undefined input instead of an empty array, and flattens array return values
- assert React.Children.only throws on arrays (including single-item arrays) and primitives, requiring a single valid React element
- assert React.cloneElement preserves keys when passed key: undefined, coerces key: null to string 'null', and gives precedence to trailing children arguments
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- test/contract.mjs