Transforms & Custom Decorators

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Overview

The Validation Library includes a set of transforms and custom decorators that provide additional functionality over the base class-validator features.

Custom Transforms

The library offers custom transforms that allow for more nuanced type coercion and value transformation.

Example Transform Usage

import { Transform } from 'class-transformer';
import { trim } from '@softkit/validation';

export class CreateUserDto {
  @Transform(trim)
  name: string;
}

Custom Decorators

Enhance validation with custom decorators for more specific use-cases, such as localized email validation and matching field checks.

When creating a sign-up form, it's crucial to validate that the user has entered the intended password correctly. This often involves having a "repeat password" field. The Validation Library provides decorators to ensure the repeated password matches the original password.

Custom Decorator Example

import { IsEmailLocalized, Match } from '@softkit/validation';

export class UserDto {
  @IsEmailLocalized()
  email: string;

  @PasswordLocalized()
  @IsStringCombinedLocalized({
    minLength: 8,
    maxLength: 256,
  })
  password: string;

  @PasswordLocalized()
  @MatchesWithProperty('password', {
    message: 'validation.REPEAT_PASSWORD_DOESNT_MATCH',
  })
  repeatedPassword: string;
}

Conclusion

By leveraging the Validation Library, your application gains a powerful suite of tools to ensure robust data validation. The additional transforms and decorators enhance the standard class-validator functionality, making your validation logic more concise and maintainable.