Validation Rules Engine Core

@validation-rules-engine/core is the framework-independent core of Validation Rules Engine (VRE). It contains validation contracts, fluent validators, built-in rules, results, and model-state utilities without importing Angular or another UI framework.

Installation

npm install @validation-rules-engine/core underscore

underscore is a peer dependency retained for validator compatibility.

Capabilities

• Define reusable policies with ValidationPolicy
• Build field validators with ValidatorHelper
• Apply built-in rules through ValidationHelper
• Represent field, required, form-group, and policy-group results
• Track touched fields and determine when errors should be visible
• Reset validation metadata and identify validation-failure shapes

Example

import {
  ValidationPolicy,
  Validator,
  ValidatorHelper
} from '@validation-rules-engine/core';

export class AccountPolicy implements ValidationPolicy {
  addValidations(v: ValidatorHelper): Validator[] {
    return [
      v.validateFor('email')
        .isRequired('Email is required')
        .isEmail('Enter a valid email address')
    ];
  }
}

Public API

• ValidationPolicy, ValidationModel
• Validator, ValidatorHelper, ValidationHelper
• ValidationError, ValidationResult, and RequiredResult
• FormGroupStatus, PolicyGroupConfig, and ControlType
• validation metadata, touched-state, reset, and failure-shape utilities

The Angular expression-based policy executor remains in @validation-rules-engine/angular because it relies on Angular's expression parser. Extracting it requires a separately tested parser abstraction.

Architecture

Core is the lowest-level package. Framework adapters may depend on it; it never depends on an adapter. The repository enforces this rule with npm run architecture:verify.

License

MIT - see LICENSE.