@slaega/db-validation

🇫🇷 Version française

@slaega/db-validation is a NestJS validation library that supports multiple ORMs (Prisma, TypeORM, MicroORM, Sequelize). It allows you to declare common database validations through a unified builder and integrate them into your services via decorators with result retrieval.

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🚀 Features

• Multi-ORM Support: Compatible with Prisma, TypeORM, MicroORM, and Sequelize
• Unified Builder: A single builder with ORM-specific methods
• Smart Validations:
  • exists (404 Not Found) - Returns the entity if found
  • ensureExists (400 Bad Request) - Returns the entity if found
  • unique (409 Conflict)
  • ensureNotExists (400 Bad Request)
  • Count validations: ensureCountAtLeast, ensureCountAtMost, ensureCountEquals
• Decorator with Results: Retrieve validated entities directly in your methods
• Type-safe: Full TypeScript support for all ORMs

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📦 Installation

yarn add @slaega/db-validation
# or
npm install @slaega/db-validation

Required Dependencies

1. NestJS Dependencies (required in all cases)

yarn add @nestjs/common @nestjs/core reflect-metadata

2. ORM-specific Dependencies

For Prisma

yarn add @prisma/client

For TypeORM

yarn add @nestjs/typeorm typeorm

For MikroORM

yarn add @mikro-orm/core @mikro-orm/nestjs

For Sequelize

yarn add @nestjs/sequelize sequelize sequelize-typescript

Module Configuration

With Prisma

import { Module } from '@nestjs/common';
import { DbValidationModule } from '@slaega/db-validation';
import { PrismaModule } from './prisma/prisma.module';
import { PrismaService } from './prisma/prisma.service';

@Module({
  imports: [
    PrismaModule,
    DbValidationModule.registerAsync({
      imports: [PrismaModule],
      useFactory: (prisma: PrismaService) => ({
        adapter: new PrismaAdapter(prisma)
      }),
      inject: [PrismaService],
    }),
  ],
})
export class AppModule {}

With TypeORM

import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';
import { DbValidationModule } from '@slaega/db-validation';
import { DataSource } from 'typeorm';

@Module({
  imports: [
    TypeOrmModule.forRoot({
      // your TypeORM config
    }),
    DbValidationModule.forRoot({
      useFactory: (dataSource: DataSource) => ({
        adapter: new TypeORMAdapter(dataSource)
      }),
      inject: [DataSource]
    })
  ]
})
export class AppModule {}

With MikroORM

import { Module } from '@nestjs/common';
import { MikroOrmModule } from '@mikro-orm/nestjs';
import { DbValidationModule } from '@slaega/db-validation';
import { MikroORM } from '@mikro-orm/core';

@Module({
  imports: [
    MikroOrmModule.forRoot({
      // your MikroORM config
    }),
    DbValidationModule.forRoot({
      useFactory: (orm: MikroORM) => ({
        adapter: new MikroOrmAdapter(orm)
      }),
      inject: [MikroORM]
    })
  ]
})
export class AppModule {}

With Sequelize

import { Module } from '@nestjs/common';
import { SequelizeModule } from '@nestjs/sequelize';
import { DbValidationModule } from '@slaega/db-validation';
import { Sequelize } from 'sequelize-typescript';

@Module({
  imports: [
    SequelizeModule.forRoot({
      // your Sequelize config
    }),
    DbValidationModule.forRoot({
      useFactory: (sequelize: Sequelize) => ({
        adapter: new SequelizeAdapter(sequelize)
      }),
      inject: [Sequelize]
    })
  ]
})
export class AppModule {}

---

⚙️ Usage

1. Using the Builder

The builder can be used directly or in a validation class. Here's the syntax for each ORM:

With Prisma

import { ValidationBuilder } from '@slaega/db-validation';

// Using model names as strings
const builder = ValidationBuilder
  .forPrisma()
  .ensureExists('User', { id: 1 })
  .unique('Post', { title: 'My title' });

With TypeORM

import { ValidationBuilder } from '@slaega/db-validation';
import { User } from './entities/user.entity';
import { Post } from './entities/post.entity';

// Using Entity classes
const builder = ValidationBuilder
  .forTypeorm()
  .ensureExists(User, { id: 1 })
  .unique(Post, { title: 'My title' });

With MikroORM

import { ValidationBuilder } from '@slaega/db-validation';
import { User } from './entities/user.entity';
import { Post } from './entities/post.entity';

// Using Entity classes
const builder = ValidationBuilder
  .forMikroOrm()
  .ensureExists(User, { id: 1 })
  .unique(Post, { title: 'My title' });

With Sequelize

import { ValidationBuilder } from '@slaega/db-validation';
import { User } from './models/user.model';
import { Post } from './models/post.model';

// Using Sequelize models
const builder = ValidationBuilder
  .forSequelize()
  .ensureExists(User, { id: 1 })
  .unique(Post, { title: 'My title' });

2. Organization with Validation Classes

For better code organization and easier mapping with the @UseDbValidation decorator, create a validation class per service. Each class contains rules for the corresponding service methods:

import { ValidationBuilder } from '@slaega/db-validation';

// With Prisma

// post.validation-rules.ts
export class PostValidationRules {
  // Rule for PostService.create
  create(email: string, input: CreatePostDto) {
    return ValidationBuilder
      .forPrisma()
      .ensureExists('Author', { email }, {
        message: 'Author not found',
        code: 'AUTHOR_NOT_FOUND'
      })
      .ensureNotExists('Post', { title: input.title }, {
        message: 'Title already exists',
        code: 'TITLE_DUPLICATE'
      });
  }
}

// 2. Using in service with result retrieval
@Injectable()
export class PostService {
  constructor(
    private readonly repo: PostRepository,
    private readonly dbValidationService: DbValidationService, // The attribute name doesn't matter
  ) {}

  // Note: The decorator automatically detects DbValidationService in the service
  // If you extend or modify DbValidationService, you must specify the getter:
  // @UseDbValidation(PostValidationRules, 'create', (self) => self.dbValidationService)
  //
  // Otherwise, automatic detection is sufficient:

  @UseDbValidation(PostValidationRules, 'create')
  async createPost(
    email: string,
    input: CreatePostDto,
    options?: ValidationOptions
  ) {
    // Results are in validation order
    const [authorResult, _] = options?.validationResult ?? [];

    // authorResult contains the Author object directly
    const author = authorResult;

    // You can use the validated author data
    return this.repo.create({
      ...input,
      authorId: author.id,
    });
  }
}

The validation flow:

1. The decorator executes rules defined in PostValidationRules.create
2. ensureExists checks the author and returns its data if found
3. ensureNotExists verifies the title doesn't exist
4. Results are passed to the method via options.validationResult
5. You can use validated data (e.g., author) in your logic

3. Usage without Decorator

You can also use the validator directly:

const builder = new PostValidationRules().create(userId, input);
const results = await dbValidatorService.validate(builder);

// Access results
const [userResult] = results; 

console.log(userResult)

---

🧩 Validation Methods

HTTP Code Behavior

Validation	Condition	HTTP Code	Exception	OK Result
exists	Record found	404	NotFoundException	✅ Found object
ensureExists	Record found	400	BadRequestException	✅ Found object
unique	No duplicate	409	ConflictException	✅ true
ensureNotExists	No duplicate	400	BadRequestException	✅ true
ensureCountAtLeast	Count ≥ min	400	BadRequestException	✅ { count: number }
ensureCountAtMost	Count ≤ max	400	BadRequestException	✅ { count: number }
ensureCountEquals	Count = val	400	BadRequestException	✅ { count: number }

Result Examples

// For exists/ensureExists
const [userResult] = await service.validate(builder);
console.log(userResult); // { id: 1, email: 'user@example.com', ... }

// For unique/ensureNotExists
const [uniqueResult] = await service.validate(builder);
console.log(uniqueResult); // true

// For count validations
const [countResult] = await service.validate(builder);
console.log(countResult); // { count: 5 }

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🧪 Local Testing

1. Clone & install

   git clone https://github.com/slaega/db-validation.git
   cd db-validation
   yarn install

2. Build

   yarn build

3. Link in a project

   yarn link
   cd ../your-app
   yarn link @slaega/db-validation
   yarn install

4. Tests

   yarn test
   yarn test:watch

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🤝 Contributing

1. Fork the repo
2. Create a branch (git checkout -b feature/my-feature)
3. Commit your changes (git commit -m 'Add feature')
4. Push to your branch (git push origin feature/my-feature)
5. Open a Pull Request

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📄 License

This project is under the MIT license. See LICENSE for more details.

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Maintained by Slaega. Feel free to open issues on GitHub!