Getting Started

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The Validation Library is a comprehensive wrapper around the class-validator package, providing enhanced features and integrations for the Softkit ecosystem.

Enhanced Integration

This library is closely integrated with @softkit/i18n to facilitate the easy overriding of default translations, streamlining internationalization efforts in your projects.

Improved Transformers

Beyond the standard class-validator capabilities, the Validation Library offers better transformers for handling types like dates and booleans, which are often mishandled by the default transformers.

Installation

yarn add @softkit/validation

Basic Usage

Use the Validation Library just as you would with the standard class-validator, with the additional benefit of enhanced features and integrations:

Dynamic Validator Usage

The library enhances the validation process with dynamic validation schemas and customized error handling:

• To validate enum values and throw an exception if the value does not match the expected enum:

import {
  validateAndThrow,
  IsEnumValidatorDefinition,
} from '@softkit/validation';

validateAndThrow(IsEnumValidatorDefinition, 'fieldName', 'fieldValue', [
  'enumValue1',
  'enumValue2',
]);

• To validate against a regular expression and throw an exception if the value does not comply:

import {
  MatchesRegexpValidatorDefinition,
  validateAndThrow,
} from '@softkit/validation';

const constraint = /^-?(?!0\d)\d+$/;

validateAndThrow(
  MatchesRegexpValidatorDefinition,
  'fieldName',
  'fieldValue',
  constraint,
  i18nString('validation.INTEGER'),
);

• If immediate exception throwing is not desired, use validateAndReturnError to return a ValidationError object for later use:

import {
  IsEnumValidatorDefinition,
  validateAndReturnError,
} from '@softkit/validation';

const error = validateAndReturnError(
  IsEnumValidatorDefinition,
  'fieldName',
  'fieldValue',
  ['enumValue1', 'enumValue2'],
);

if (error) {
  console.log(error);
}

Method Validation Rules

The library also enables method-specific validation rules, which you can reference here. These rules ensure that your validations are precise and context-aware, providing a richer set of constraints for your data.

Error Handling

Should a validation not meet the defined schema, the library will throw an exception. This exception is designed to be caught by a filter that returns an RFC7807-compliant error response, ensuring consistent error handling throughout your application.

Next Steps

• For a detailed breakdown of default settings and custom transformers, proceed to the Transforms & Custom Decorators section.