Sample
react 19.0.0: Assert React 19.0.0 element construction, transitional symbol typing, ref-as-prop placement, self-referencing context providers, cloneElement immutability, and hierarchical Children tree traversal
Verified sample for npm react 19.0.0: Assert React 19.0.0 element construction, transitional symbol typing, ref-as-prop placement, self-referencing context…
sha256:c8b98eea95c66b47e111cdc80a70e476f4d7403393566d55915970c58faaaf08
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
- Assert React 19.0.0 element construction, transitional symbol typing, ref-as-prop placement, self-referencing context providers, cloneElement immutability, and hierarchical Children tree traversal
- Packages
- Symbols
-
- React.createElement
- React.cloneElement
- React.createContext
- React.Children
- React.isValidElement
- React.createRef
- React.memo
- React.forwardRef
- React.lazy
- Environment
- node
- Created
- 2026-08-17T20:12:28Z
Contract
- React 19 createElement produces elements with Symbol.for('react.transitional.element') typeof where ref is stored directly as a prop on props.ref rather than an element property.
- React.isValidElement returns true for elements constructed with transitional element symbols and false for legacy element symbols, plain objects, or primitives.
- React.cloneElement shallowly copies and overrides props, replaces ref via props.ref, and preserves the original element immutability.
- React.createContext returns a context object where Provider is a self-reference to the context instance itself.
- React.Children.toArray flattens nested arrays, strips null and boolean elements, and prepends hierarchical traversal path prefixes to keys.
- React.Children.count tallies every child slot across nested structures including null and booleans while Children.only asserts a single child element.
- React.Children.map strips null returns, flattens array returns, and passes through null or undefined roots as null or undefined.
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- test/contract.mjs