Rules

Built-in Rules

R-Think includes a set of built-in rules covering common validation patterns.

• required - Ensures a field is present.
• type - Validates the JavaScript type of a field.
• bounded - Validates numeric ranges.
• matches - Validates against a regular expression.
• enum - Validates against a set of allowed values.
• minLength / maxLength - Validates string or array length.
• custom - Defines validation logic with a function.

Defining Rules

Rules are defined as an array and attached to a runtime or protocol. They are evaluated automatically before each step executes.

import { Rule } from '@r-think/core';

const rules = [
  Rule.required('applicationId'),
  Rule.type('applicationId', 'string'),
  Rule.matches('email', /^[^\s@]+@[^\s@]+\.[^\s@]+$/),
  Rule.bounded('score', 0, 100),
  Rule.enum('status', ['pending', 'approved', 'rejected']),
  Rule.custom('riskLevel', (value) => {
    return value >= 0 && value <= 10;
  }, 'Risk level must be between 0 and 10')
];

Custom Rules

When built-in rules are insufficient, define custom rules using the Rule.custom factory. The validator function receives the value and context, returning true for pass or a string error message for fail.

Rule.custom('portfolio', (value, ctx) => {
  if (!Array.isArray(value)) return 'Portfolio must be an array';
  if (value.length === 0) return 'Portfolio cannot be empty';
  const hasValidAssets = value.every(asset => asset.value > 0);
  if (!hasValidAssets) return 'All assets must have positive value';
  return true;
}, 'Portfolio validation failed');

Rule Groups

Rules can be grouped and applied conditionally. Use RuleGroup to organize rules by concern: input validation, output validation, and transition validation.