@alexcatdad/prisma-dto-generator

A Prisma generator that automatically creates NestJS DTOs (Data Transfer Objects) with Swagger/OpenAPI decorators from your Prisma schema.

Features

• 🎯 Automatic DTO Generation: Generates Create, Update, and Read DTOs for all Prisma models
• 📝 Swagger Integration: Automatically adds Swagger decorators for OpenAPI documentation
• ✅ Validation: Includes class-validator decorators for type-safe validation
• 🔗 Relation Handling: Configurable handling of Prisma relations (omit, ids, or nested)
• 📁 Domain Structure: Optional domain-based folder organization
• 🔤 Enum Support: Generates TypeScript enums from Prisma enums
• 🎨 Customizable: Extensive configuration options for different use cases

Inspiration

This package is heavily inspired by:

• @brakebein/prisma-generator-nestjs-dto
• prisma-generator-nestjs-dto

However, these packages did not work in some projects due to changes in the latest Prisma and NestJS versions. This package was created as a simplified, modern alternative that works with current versions of Prisma (v6+) and NestJS (v10+).

Installation

# npm
npm install --save-dev @alexcatdad/prisma-dto-generator

# yarn
yarn add -D @alexcatdad/prisma-dto-generator

# pnpm
pnpm add -D @alexcatdad/prisma-dto-generator

# bun
bun add -d @alexcatdad/prisma-dto-generator

Quick Start

1. Add the generator to your schema.prisma:

generator nestdto {
  provider = "@alexcatdad/prisma-dto-generator"
  output   = "./dto"
}

2. Run Prisma generate:

# npm
npx prisma generate

# yarn
yarn prisma generate

# pnpm
pnpm prisma generate

# bun
bunx prisma generate

3. Use the generated DTOs in your NestJS controllers:

import { CreateUserDto } from './dto/create-user.dto'
import { UpdateUserDto } from './dto/update-user.dto'

@Controller('users')
export class UserController {
  @Post()
  create(@Body() createUserDto: CreateUserDto) {
    // ...
  }

  @Patch(':id')
  update(@Param('id') id: string, @Body() updateUserDto: UpdateUserDto) {
    // ...
  }
}

Configuration

Basic Configuration

generator nestdto {
  provider        = "@alexcatdad/prisma-dto-generator"
  output          = "./dto"
  emitBarrel      = "true"           // Generate index.ts barrel file
  relations       = "ids"             // How to handle relations: "omit" | "ids" | "nested"
  folderStructure = "flat"            // "flat" | "domain"
  heuristics      = "true"            // Apply smart field type detection
  clean           = "true"            // Clean output directory before generation
}

Advanced Configuration

generator nestdto {
  provider        = "@alexcatdad/prisma-dto-generator"
  output          = "./dto"
  folderStructure = "domain"
  domainMapping   = "./dto-domain-mapping.json"
  dateStrategy    = "iso-string"      // "iso-string" | "date"
  jsonType        = "Record<string, unknown>"
  fileNaming      = "kebab"           // "kebab" | "camel" | "pascal"
  omitFields      = "{\"User\": [\"password\", \"secretKey\"]}"
  readDtoInclude  = "{\"User\": [\"profile\", \"posts\"]}"
}

Configuration Options

emitBarrel (boolean, default: true)

Generate an index.ts barrel file that exports all DTOs.

relations ("omit" | "ids" | "nested", default: "ids")

How to handle Prisma relations in DTOs:

• omit: Exclude all relation fields
• ids: Include only the foreign key IDs (e.g., userId: string)
• nested: Include nested relation objects

folderStructure ("flat" | "domain", default: "flat")

• flat: All DTOs in a single directory
• domain: Organize DTOs by domain (requires domainMapping)

domainMapping (JSON string or file path, optional)

Map Prisma models to domain folders. You can provide this in two ways:

Option 1: JSON file (Recommended for better DX)

Create a dto-domain-mapping.json file:

{
  "User": "users/user",
  "Post": "content/post",
  "Comment": "content/comment"
}

Then reference it in your schema:

generator nestdto {
  provider        = "@alexcatdad/prisma-dto-generator"
  output          = "./dto"
  folderStructure = "domain"
  domainMapping   = "./dto-domain-mapping.json"
}

Option 2: Inline JSON string

domainMapping = "{\"User\": \"users/user\", \"Post\": \"content/post\", \"Comment\": \"content/comment\"}"

Note: Domain mappings are optional and must be explicitly provided. There are no built-in defaults, making the package generic for any project.

dateStrategy ("iso-string" | "date", default: "iso-string")

• iso-string: Use string type with ISO date format
• date: Use TypeScript Date type

jsonType (string, default: "Record<string, unknown>")

TypeScript type for Prisma Json fields.

fileNaming ("kebab" | "camel" | "pascal", default: "kebab")

Naming convention for generated DTO files:

• kebab: create-user.dto.ts
• camel: createUser.dto.ts
• pascal: CreateUser.dto.ts

heuristics (boolean, default: true)

Apply smart field type detection:

• Fields containing "email" → @IsEmail()
• Fields containing "url" → @IsUrl()
• Fields ending with "Id" → @IsUUID()

omitFields (JSON string, optional)

Exclude specific fields from Create/Update DTOs. Format: {"ModelName": ["field1", "field2"]}

readDtoInclude (JSON string, optional)

Include specific relation fields in Read DTOs. Format: {"ModelName": ["relation1", "relation2"]}

clean (boolean, default: false)

Remove all files in the output directory before generation.

Generated DTO Structure

CreateDTO

Contains all fields required for creating a new entity (excluding id, createdAt, updatedAt).

UpdateDTO

Extends PartialType(CreateDTO) from @nestjs/swagger, making all fields optional.

ReadDTO

Contains all fields including id, createdAt, updatedAt, and optionally nested relations.

Domain-Based Folder Structure

When using folderStructure = "domain" with domainMapping, DTOs are organized like:

dto/
  users/
    user/
      create-user.dto.ts
      update-user.dto.ts
      read-user.dto.ts
  content/
    post/
      create-post.dto.ts
      update-post.dto.ts
      read-post.dto.ts

Examples

See the examples/ directory for:

• Basic: Simple setup with minimal configuration
• Advanced: Complex schema with relations, enums, and custom mappings
• NestJS Integration: Full controller and service examples

Requirements

• Node.js >= 16
• Prisma >= 6.0.0
• NestJS >= 10.0.0
• TypeScript >= 5.0.0

Dependencies

The generated DTOs require:

• @nestjs/swagger
• class-validator
• class-transformer

Install them:

# npm
npm install @nestjs/swagger class-validator class-transformer

# yarn
yarn add @nestjs/swagger class-validator class-transformer

# pnpm
pnpm add @nestjs/swagger class-validator class-transformer

# bun
bun add @nestjs/swagger class-validator class-transformer

Troubleshooting

DTOs not generating

• Ensure the generator is added to schema.prisma
• Run npx prisma generate (or yarn prisma generate, pnpm prisma generate, bunx prisma generate)
• Check the output path is correct

Domain mappings not working

• Verify folderStructure = "domain" is set
• Ensure domainMapping is valid JSON string
• Check model names match your Prisma schema exactly (case-sensitive)

Missing decorators

• Ensure @nestjs/swagger, class-validator, and class-transformer are installed
• Check that your NestJS version supports the decorators used

Type errors

• Ensure all dependencies are installed
• Run npx prisma generate (or yarn prisma generate, pnpm prisma generate, bunx prisma generate) after schema changes
• Check TypeScript version compatibility

License

MIT

Contributing

See CONTRIBUTING.md for development guidelines.

Changelog

See CHANGELOG.md for version history.