Prisma Class Validator Generator


💖 Support This Project

If this tool helps you build better applications, please consider supporting its development:

Your sponsorship helps maintain and improve this project. Thank you! 🙏

✨ Features

- 🏗️ Auto-generation - Automatically generates TypeScript models with class-validator decorators
- 🔧 Prisma 6 support - Full compatibility with the latest Prisma features and types
- 🎯 Type safety - Perfect TypeScript integration with proper type inference
- 📝 Smart decorators - Intelligent mapping of Prisma types to class-validator decorators
- 🔄 Incremental updates - Regenerates only when schema changes
- 🚀 Zero config - Works out of the box with sensible defaults
- 🛡️ Production ready - Battle-tested with comprehensive test coverage
- 📦 Lightweight - Minimal dependencies and fast generation

🚀 Quick Start

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``bash


npm

> Heads up: Keep a Prisma Client generator in the same schema. Both provider = "prisma-client" (recommended) and provider = "prisma-client-js" are supported.

`prisma
generator client {
provider = "prisma-client" // or "prisma-client-js"
output = "../generated/prisma-client" // required when using prisma-client
}

generator class_validator {
provider = "prisma-class-validator-generator"
output = "./generated" // optional, defaults to ./generated
}

model User {
id Int @id @default(autoincrement())
email String @unique
name String?
posts Post[]
}

model Post {
id Int @id @default(autoincrement())
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
title String
content String?
published Boolean @default(false)
viewCount Int @default(0)
author User? @relation(fields: [authorId], references: [id])
authorId Int?
rating Float
}
`

2. Generate your models:

`bash
npx prisma generate
`

3. Use the generated classes:

`typescript
import { User } from './generated/models';
import { validate } from 'class-validator';

const user = new User();
user.id = 1;
user.email = 'user@example.com';
user.name = 'John Doe';

const errors = await validate(user);
if (errors.length > 0) {
console.log('Validation failed:', errors);
} else {
console.log('User is valid!');
}
`

🎯 Generated Output

The generator creates TypeScript classes with appropriate class-validator decorators:

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@IsDefined()
posts!: Post[];
}
`

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@IsDefined()
@IsNumber()
rating!: number;
}
`

🔧 Configuration Options

Customize the generator behavior:

`prisma
generator class_validator {
provider = "prisma-class-validator-generator"
output = "./src/models" // Output directory
swagger = "true" // Add Swagger decorators
separateRelationFields = "true" // Split base/relation classes
}
`

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| Option | Type | Default | Description |
|--------|------|---------|-------------|
| output | string | "./generated" | Output directory for generated models |
| swagger | string | "false" | Add NestJS @ApiProperty decorators for Swagger docs |
| separateRelationFields | string | "false" | Generate separate base and relation classes for flexible DTOs |

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Automatically generates NestJS Swagger decorators alongside class-validator decorators:

`typescript
export class User {
@IsDefined()
@ApiProperty({ example: 'Generated by autoincrement', type: "integer" })
@IsInt()
id!: number;

@IsDefined()
@ApiProperty({ type: "string" })
@IsString()
email!: string;

@IsOptional()
@ApiProperty({ type: "string", required: false })
@IsString()
name?: string | null;
}
`

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Perfect for NestJS DTOs - generates separate classes for maximum flexibility:

- UserBase.model.ts - Only scalar fields with validation decorators
- UserRelations.model.ts - Only relation fields
- User.model.ts - Combined class extending UserBase

This enables powerful NestJS patterns:
`typescript
// Create DTO without relations using PickType
export class CreateUserDto extends PickType(UserBase, ['email', 'name']) {}

// Update DTO with partial fields
export class UpdateUserDto extends PartialType(UserBase) {}

// Full model with relations for responses
export class UserResponseDto extends User {}
`

📚 Advanced Usage

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`prisma
enum Role {
USER
ADMIN
MODERATOR
}

model User {
id String @id @default(cuid())
email String @unique
name String?
role Role @default(USER)
profile Profile?
posts Post[]
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
}

model Profile {
id String @id @default(cuid())
bio String?
avatar Bytes?
user User @relation(fields: [userId], references: [id])
userId String @unique
}

model Post {
id String @id @default(cuid())
title String
content String?
published Boolean @default(false)
tags String[]
metadata Json?
author User @relation(fields: [authorId], references: [id])
authorId String
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
}
`

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`typescript
export enum Role {
USER = "USER",
ADMIN = "ADMIN",
MODERATOR = "MODERATOR",
}
`

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`typescript
import { IsString, IsDefined, IsEmail, IsOptional, IsEnum, IsDate } from "class-validator";
import { Role } from "../enums";
import { Profile } from "./Profile.model";
import { Post } from "./Post.model";

export class User {
@IsDefined()
@IsString()
id!: string;

@IsDefined()
@IsEmail()
email!: string;

@IsOptional()
@IsString()
name?: string | null;

@IsDefined()
@IsEnum(Role)
role!: Role;

@IsOptional()
profile?: Profile | null;

@IsDefined()
posts!: Post[];

@IsDefined()
@IsDate()
createdAt!: Date;

@IsDefined()
@IsDate()
updatedAt!: Date;
}
`

🧪 Testing

The generator includes comprehensive tests covering:

- Basic model generation
- Complex schemas with relations
- Enum generation
- Edge cases and error handling
- TypeScript compilation

Run tests:

`bash
npm test # Run tests in watch mode
npm run test:ci # Run tests once with coverage
npm run test:coverage # Generate coverage report
`

🔍 Type Mapping

The generator intelligently maps Prisma types to class-validator decorators:

| Prisma Type | TypeScript Type | Class Validator Decorator |
|-------------|-----------------|---------------------------|
| String | string | @IsString() |
| Int | number | @IsInt() |
| Float | number | @IsNumber() |
| Boolean | boolean | @IsBoolean() |
| DateTime | Date | @IsDate() |
| Bytes | Uint8Array | @IsDefined() |
| Json | any | @IsDefined() |
| String[] | string[] | @IsArray() |
| Enum | EnumType | @IsEnum(EnumType) |
| Optional fields | type \| null | @IsOptional() |
| Required fields | type | @IsDefined() |

🤝 Contributing

We welcome contributions! Please see our Contributing Guide for details.

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`bash
git clone https://github.com/omar-dulaimi/prisma-class-validator-generator.git
cd prisma-class-validator-generator
npm install
npm run build
npm test
`

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`bash
npm run build # Compile TypeScript
npm run start # Build and run Prisma generate
npm test # Run tests in watch mode
npm run test:ci # Run tests with coverage
npm run format # Format code with Prettier
`

📖 API Reference

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The generator accepts the following configuration in your schema.prisma:

`prisma
generator class_validator {
provider = "prisma-class-validator-generator"
output = "./generated" // Optional: output directory
}
`

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`
generated/
├── models/
│ ├── User.model.ts
│ ├── Post.model.ts
│ └── index.ts
├── enums/
│ ├── Role.ts
│ └── index.ts
└── index.ts
`

🐛 Troubleshooting

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1. Generator not found: Ensure you've installed the package as a dependency
2. Output directory errors: Check that the parent directory exists
3. Import errors: Make sure class-validator is installed in your project

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Enable debug logging by setting the DEBUG environment variable:

`bash
DEBUG=prisma:generator npx prisma generate
``

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

- Built for the amazing Prisma ecosystem
- Powered by class-validator for robust validation
- Uses ts-morph for TypeScript AST manipulation

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