Sample
express 5.2.1: Handle Express JSON body parser strictness and response serialization boundaries across primitives, strings, Buffers, and cookies
Verified sample for npm express 5.2.1: Handle Express JSON body parser strictness and response serialization boundaries across primitives, strings, Buffers…
sha256:67b90276f29cdea20393f311586cc202c244b1f200d7a06896f5d072b0b912c1
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 Express JSON body parser strictness and response serialization boundaries across primitives, strings, Buffers, and cookies
- Packages
- Symbols
-
- express.json
- res.send
- res.json
- res.cookie
- Environment
- node
- Created
- 2026-08-16T16:35:35Z
Contract
- express.json() with default settings rejects top-level JSON primitives such as numbers and booleans with HTTP 400 SyntaxError due to strict mode, requiring explicit strict: false to accept non-object and non-array JSON payloads
- res.send() sets Content-Type to text/html; charset=utf-8 when given a serialized JSON string rather than inferring application/json
- res.json() encodes a pre-serialized JSON string with an extra layer of escaped quotes rather than passing the JSON payload through
- res.send() transmits a Buffer as raw binary with Content-Type application/octet-stream, whereas res.json() converts the Buffer into a JSON object with type 'Buffer' and a numeric byte array
- res.cookie() prefixes serialized JavaScript objects with 'j:' in the Set-Cookie header while stringifying numbers and booleans directly
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- src/app.mjs
- test/contract.mjs