Support Custom Validation Libraries

Description

Fireorm is tightly coupled with class-validator for model validation. To provide flexibility, we should allow the use of arbitrary validation libraries. This would involve decoupling Fireorm from class-validator and introducing a validation interface that can accommodate various validation libraries.

Steps to Reproduce

Attempt to use a validation library other than class-validator with Fireorm.
Notice the tight coupling with class-validator and the difficulty in substituting another library.

Expected Behavior

Ability to use any validation library with Fireorm by providing a custom validator through the initialization options.

Actual Behavior

Fireorm is tightly coupled with class-validator, making it challenging to use other validation libraries.

Acceptance Criteria

Introduce a validation interface that supports various validation libraries.
Modify the initialization options to accept a custom validator.
Ensure backward compatibility with the current class-validator usage.
Add unit tests to validate the functionality with different validation libraries.

Additional Context

March 16, 2022: Initial proposal to support arbitrary validation libraries.
March 16, 2022: Agreement on the idea and suggestion to use a type parameter for the validation errors.
March 17, 2022: Discussion about the tight coupling with class-validator and the complexity of decoupling.

Proposed API Changes

Introduce Validation Interface:

Define a validation interface to support various validation libraries.

interface IEntityValidator {
 (entity: IEntity, validateOptions?: Record<string, unknown>): Array<unknown>;
}

Update Initialization Options:

Modify the initialization options to accept a custom validator.

interface IFireormInitOptions  {
 validateModels?: boolean;
 validate?: IEntityValidator;
}

function initialize(firestore: Firestore, options: IFireormInitOptions = {}) {
 // Existing initialization logic...
 if (options.validateModels && options.validate) {
   this.validator = options.validate;
 } else {
   // Default to class-validator
   const { validate } = require('class-validator');
   this.validator = validate;
 }
}

Decouple Fireorm from class-validator:

Refactor the codebase to use the validation interface instead of directly relying on class-validator.

class Repository {
 async create(entity: IEntity) {
   if (this.config.validateModels) {
     const errors = this.config.validator(entity);
     if (errors.length) {
       throw errors;
     }
   }
   // Existing create logic...
 }
}

Unit Tests:

Add unit tests to validate the functionality with different validation libraries.

test('should validate entity using custom validator', async () => {
 const customValidator: IEntityValidator = (entity) => {
   if (!entity.name) return ['Name is required'];
   return [];
 };

 initialize(firestore, { validateModels: true, validate: customValidator });

 const repo = getRepository(MyEntity);
 const entity = new MyEntity();
 entity.name = '';

 await expect(repo.create(entity)).rejects.toEqual(['Name is required']);
});

Example Implementation

import { getFirestore } from 'my-firestore-setup';
import { initialize } from 'fireorm';

class MyValidator implements IEntityValidator {
  validate(entity: IEntity, validateOptions?: Record<string, unknown>): Array<unknown> {
    const errors = [];
    if (!entity.name) errors.push('Name is required');
    return errors;
  }
}

const customValidator = new MyValidator().validate;

initialize(getFirestore(), { validateModels: true, validate: customValidator });

@Collection("myEntities")
class MyEntity {
  id: string;
  name: string;
}

const repo = getRepository(MyEntity);
const entity = new MyEntity();
entity.id = "1";
entity.name = "";

await repo.create(entity); // Should throw 'Name is required'

Original Issue

elersong / fireorm24