@drzl/generator-nestjs

Generate NestJS DTO and entity classes from a Drizzle schema: per table, the insert, update, select and params shapes as plain classes whose fields state the parsed result and whose static schema carries a Standard Schema v1 validator, plus a small emitted SchemaValidationPipe that runs it. The controllers stay yours.

Why plain classes, not class-validator decorators

Settled from the registry and from measurement rather than taste. @nestjs/common lists class-validator and class-transformer as optional peers, and class-transformer, the half that would convert wire values, last published in 2021. Measured on class-validator 0.15.1: what a decorator DTO accepts depends on the consumer's pipe options rather than the DTO (enableImplicitConversion reads "" as 0, "0x10" as 16 and "1e5" as 100000, the exact family DRZL's route generators refuse); @IsOptional() cannot tell { bio: null } from {}; bigint has no story at all; and @Type(() => Date) accepts "1" as the year 2001. A static schema carries its policy with it, and no pipe option can loosen it.

The plain classes also compile under every tsconfig: no experimentalDecorators needed in the generated files (class-validator decorators fail TS1240 without it, measured). Your app keeps its standard Nest flags; the generated code does not require them.

Install

npm install -D @drzl/generator-nestjs

The generated code imports @nestjs/common (which a Nest app has by definition) and the validation library you chose: zod by default, valibot or arktype via validation.library.

Configure

import { defineConfig } from '@drzl/cli/config';

export default defineConfig({
  schema: 'src/db/schema.ts',
  outDir: 'src/dto',
  generators: [{ kind: 'nestjs', path: 'src/dto' }],
});

Consume

import { Body, Controller, Param, Patch, Post } from '@nestjs/common';
import { CreateUsersDto, UpdateUsersDto, UsersParamsDto } from './dto/index.js';

@Controller('users')
export class UsersController {
  @Post()
  create(@Body() body: CreateUsersDto) {
    // body is the parsed output: undeclared keys stripped, wire forms transformed.
  }

  @Patch(':id')
  update(@Param() params: UsersParamsDto, @Body() body: UpdateUsersDto) {
    // params.id is a real number, parsed by the strict segment schema.
  }
}

import { SchemaValidationPipe } from './dto/index.js';

app.useGlobalPipes(new SchemaValidationPipe());

The shape of the DTOs

• Create<T>Dto is the insert shape: generated columns absent, and a column the database can fill in optional. That means a defaulted column, and also a nullable one, because an INSERT that omits a nullable column stores NULL (measured against a real Postgres).
• Update<T>Dto is all-optional with the primary key columns excluded, so an id in a PATCH body is an undeclared key and is stripped.
• <T>ParamsDto parses key segments strictly: ^-?\d+(\.\d+)?$ into a number, digits kept as a string for bigint, strict ISO datetime into a Date, the member set for an enum. The Number('') family ("", " ", "0x10", "1e5") is refused; Nest's own ParseIntPipe is nearly as strict but silently rounds "9007199254740993" (measured).
• <T>Entity is one row at its select shape. Date columns are Date; bigint columns stay digit strings on both sides, because JSON.stringify throws on a real bigint.
• Every class pairs with its schema through a typed static, so schema-vs-field drift is a compile error inside the generated file. The pipe validates any class carrying one and passes everything else through untouched.

Docs

https://use-drzl.github.io/drzl/generators/nestjs

License

Apache-2.0