Sample

Observe how superjson's metadata format versioning (meta.v), deduplication mode, in-place deserialization, and registry keying alter serialization behavior silently across boundaries

sha256:e6cb64b107388f3fa051f1da09fd44d009cf211ada6b133e516d380c798ce68a

Case

Goal

Observe how superjson's metadata format versioning (meta.v), deduplication mode, in-place deserialization, and registry keying alter serialization behavior silently across boundaries HOW

Packages

superjson 2.2.6

Environment

node

Created

2026-08-16T06:23:09Z

Contract

• assert meta.v is 1 in modern superjson and escapes dots with backslashes so dotted keys round-trip intact
• assert unversioned or legacy meta.v < 1 payloads silently misroute dotted paths to nested sibling properties, leaving the top-level key as a string and creating an Invalid Date without throwing
• assert deserialize defaults to inPlace: false via a deep clone leaving the input payload untouched, whereas inPlace: true directly mutates payload.json into live runtime objects
• assert parse uses inPlace: true internally on the parsed JSON tree rather than cloning
• assert dedupe: false preserves full duplicate structures in json while annotating referential equalities, allowing non-superjson consumers to read the payload
• assert dedupe: true replaces duplicate object instances with null in json, causing silent data loss for plain JSON consumers while superjson restores referential equality
• assert circular references write null at the cycle point and restore referential equality on deserialization in both modes
• assert registerSymbol without an explicit identifier keys by description, so registering two distinct symbols with identical descriptions silently causes the second to overwrite the first upon deserialization
• assert registerClass with allowProps silently strips any unlisted properties from the serialized JSON payload
• assert registerCustom does not recursively walk the returned structure, treating its output as a terminal leaf and leaving inner types unannotated
• assert superjson strictly forbids prototype pollution keys (__proto__, constructor, prototype) by throwing during serialization, unlike standard JSON.stringify

Files

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

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

csx-seed

Verification receipts

• node 22 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-16 · ed25519:d91480838ac982c9