Synchronous API
---------------
Nothing on the default path is genuinely asynchronous - only a serializer,
deserializer or validator the caller supplies can be - so requiring `await`
everywhere taxed the common case.
Rather than duplicating the traversal into a second sync copy (the traversal is
exactly where the eight defects fixed in 0.1.0 lived, and two copies would drift),
the engines are now written synchronously and anything a hook makes asynchronous
is recorded and reconciled once at the end. A `*Sync` call that encounters a
Promise raises a JsonMappingError naming the async alternative instead of
returning a half-built object.
Adds validateSync, validateOrRejectSync, toPlainSync, toJsonSync, toInstanceSync,
toInstanceArraySync, fromJsonSync, fromJsonArraySync. fromRequest has no
synchronous form, since reading a request body is inherently async.
Removing the per-property await also sped up the async path substantially. With
the plan caching from the previous release, against JSON.parse + JSON.stringify
(5.8 us) as a fixed reference:
validate (50 orders) 221.6 us -> 17.8 us 12.4x
validate (10 orders) 47.8 us -> 4.5 us 10.6x
toPlain (50 orders) 294.4 us -> 36.0 us 8.2x
toInstance (50 orders) 255.1 us -> 31.7 us 8.0x
toInstance (single) 19.8 us -> 5.2 us 3.8x
Write-only redaction
--------------------
A @JsonWriteOnly password that failed @MinLength put the rejected password into
ValidationError.value, and from there into any log that recorded the error.
Values of properties that never leave the process - @JsonWriteOnly and
@JsonIgnore - are now replaced with the exported REDACTED placeholder. The
property name and failure message are unchanged, so the error stays actionable.
Tests
-----
176 tests, up from 150. The new suite covers the sync family, its refusal of
async hooks (including that refusing does not leave an unhandled rejection), and
async hooks through the async API - serializers, deserializers, validators, and
async validators under each: true, which the suite had never exercised.
That last group caught a regression this change introduced: with an async
serializer the deferred write appended its key after the synchronous ones,
changing property order in the output. The slot is now claimed before deferring.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SAcqrz3FcadkYr3xG32CjK
Profiling the validator showed roughly half of all validation time re-deriving
answers that cannot change — collectConstraints 22%, getOwnMetadata 12%,
getMetadataChain 9%, getProperties 4%, getMetadata 3%, plus 8% GC from the
allocation churn. The constraint predicates themselves were under 1%.
Decorator metadata is fixed once classes are declared, so the derived structures
are now memoized per prototype: the validation plan, the serialization plan, the
deserialization plan, and serializer/deserializer instances, which were being
constructed fresh for every property of every object. MetadataStorage carries a
version counter that invalidates the caches when metadata is written, so
registerDecorator after first use still works — covered by a test.
Measured against JSON.parse + JSON.stringify as a fixed reference:
validate (50 orders) 221.6 us -> 49.6 us 4.5x
validate (10 orders) 47.8 us -> 12.9 us 3.7x
toInstance (50 orders) 255.1 us -> 74.0 us 3.4x
toInstance (10 orders) 64.6 us -> 19.0 us 3.4x
toPlain (50 orders) 294.4 us -> 95.3 us 3.1x
Reliability, in the same pass:
- maxDepth option (default 64) on every mapping function, on validate(), and on
configure(). All three engines recurse, so a payload nested thousands of levels
deep could exhaust the call stack. Cycles were already handled; legitimate deep
nesting was not bounded.
- each: true failures now name the element that failed ("failed at index 3"). A
bad entry in a 200-item array previously produced a message that could not
locate it. A message function now receives the failing element as args.value
rather than the whole array; caller-supplied strings stay verbatim.
150 tests (up from 136), all green on the existing suite unchanged.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SAcqrz3FcadkYr3xG32CjK
The README described a library that did not exist in places. It showed
@ValidateNested({ each: true }), which did not compile; told users to enable
emitDecoratorMetadata, which the library never reads; and documented none of the
mapping API. Its Quick Start now runs verbatim — verified by compiling and
executing it against the local source.
- README: document field-name mapping, access control, options, error helpers
and the 30 new validators; drop the emitDecoratorMetadata instruction; add a
Notes and Limitations section covering circular references, validate() on
plain objects, and the fact that @JsonProperty stops the original name from
being accepted unless you add @JsonAlias
- CHANGELOG.md: new, covering 0.1.0
- example.ts: rewritten as a tour of the current API — read-only ids, write-only
secrets, renamed fields, conditional validation, flattened errors, and a
base-class rule reaching a subclass
- docs: the playground hand-listed its symbol table in three parallel places and
exposed IsEmail, which is not an export. It now derives scope from the bundle,
so new decorators work there as soon as they ship. Bundle regenerated
- version 0.1.0
136 tests, 97% statement and 100% function coverage.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SAcqrz3FcadkYr3xG32CjK
Claude