@injitools/contract

The DTO/validation layer of the Inji framework: the RequestDto/ResponseDto decorators, a metadata store, and Zod validation. It depends only on zod + reflect-metadata — no express, no got, no typeorm, no node-core. This is deliberate layering hygiene: contract is the dependency-light base that core/db/auth build on, so keeping it free of server dependencies avoids dependency cycles.

You normally do not depend on this package directly: @injitools/core depends on @injitools/contract and re-exports the entire API, so backends import from @injitools/core.

What it exports

• the RequestDto, ResponseDto decorators (the two DTO kinds) — plus Dto (deprecated alias of RequestDto) and the DtoProperty, DtoLink, DtoLinkArray field decorators;
• DtoStorage, DtoType, DtoPropertyType, DtoDirection and the metadata types (TDto*);
• generateZodValidation, generateSchema, generatePrimitiveZodValidation, detectContentType, isPrimitiveType, boolFromQueryOrJson;
• dataToDto;
• the type-level helpers Infer<typeof Dto> (output, ≡ z.infer) and InferInput<typeof Dto> (input before parsing, ≡ z.input);
• the UrlLike / UrlLikeSchema primitives, PRIMITIVE_TYPES, the PrimitiveType type;
• setOrmZodResolver / OrmZodResolver — the ORM-validation seam (the resolver is registered by @injitools/db, so typeorm never enters this graph). The resolver is direction-aware: the same column derives a request field (input semantics) or a response field (output semantics);
• the canonical ErrorResponseDto.

Decorator metadata (important)

A DTO field's type is derived from the code via design:type, so the consumer must build with a toolchain that emits decorator metadata. Otherwise @DtoProperty() without an explicit type yields Reflect.getMetadata('design:type', …) === undefined and validation fails at runtime with Unsupported primitive: undefined.

• reflect-metadata — nothing to do: the package loads it itself on the first line of the entry, before any DTO is declared (importing it again is harmless).
• tsconfig — experimentalDecorators: true, emitDecoratorMetadata: true, and (with target ≥ ES2022) useDefineForClassFields: false so class fields don't overwrite decorator metadata.
• transform — build through tsc or SWC (legacyDecorator + decoratorMetadata); esbuild/tsx do not emit metadata.

Checks (tests)

• tests/no-orm-leak.test.ts — source scan: fails if any src/** import pulls in a server dependency (typeorm/@injitools/db/@injitools/auth/express/got).
• tests/graph.test.ts — walks the built package graph: only zod + reflect-metadata allowed.
• tests/contract.unit.test.ts — a smoke test of the DTO layer: type inference from design:type, dataToDto, ErrorResponseDto.
• tests/infer.test-d.ts — type-level Infer/InferInput tests (vitest --typecheck).
• tests/infer.runtime.test.ts — a runtime check: the schema parses the input shape into the output shape exactly as the types promise (coercion, UrlLike, optional, strictObject).

npm test -w @injitools/contract