Docs / Validation and contracts

Validation & SerializationSupported

First-class pipes that bind a route to schema-derived DTO validation and entity serialization — the NestJS ValidationPipe / ClassSerializerInterceptor analogues, but zero-runtime-parser: validation is your AOT assert, so there is no Zod-style parser on the hot path.

Validation pipe#

import { validationPipe, runChain } from '@zmdb/web';
import { assert } from '@zmdb/validator';
import { type CreateDTO } from '@zmdb/schema';

// The pipe's Out type is the DTO, so the handler body is typed — no 'as'.
const pipe = validationPipe(raw => assert<CreateDTO<User>>(raw));

A body that fails validation makes the chain return 400; the handler never runs. A valid body reaches the handler typed as the DTO.

Serialization interceptor#

import { serializationInterceptor } from '@zmdb/web';

// shape the response from Entity<S> (default is identity — the pipeline
// JSON-encodes downstream)
const serializer = serializationInterceptor(entity => toPublicUser(entity));

One-call composition#

import { dtoChain } from '@zmdb/web';

const chain = dtoChain({
  validate: raw => assert<CreateDTO<User>>(raw),
  serialize: user => toPublicUser(user),
});
// → a Chain with the validation pipe + serialization interceptor pre-composed

❗ Important

Validation runs before the handler (invalid → 400) and the response is shaped after — both bound to your schema DTOs, so the request contract, the DB write and the response never drift.

Design notes#

Zero runtime parser — validation is the consumer's AOT assert; the framework embeds none.
No as — the pipe's Out type is the DTO, so the handler body is typed by the pipe.
Granular import: import { dtoChain } from '@zmdb/web/dto-pipes'.

Cross-links#

Guards, pipes, interceptors & filters · Building an API with zmdb · AOT setup

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