Error Handling

Typyn's UnisafeError provides paths and messages for precise debugging. Extend for aggregation, localization, or UI mapping.

Step-by-Step Example (Aggregation)

1. Basic Catch: Log full error.
2. Aggregate: Collect multi-field errors.
3. Custom Refine: Add business rules.

Full Code (Node Utility)

import { v } from 'typyn';

const profileSchema = v.object({
  bio: v.string().max(200).refine((s) => s.split(' ').length > 5, 'Too short (min 5 words)'),
  hobbies: v.array(v.string()).min(1)
});

// Aggregate errors (custom extension)
function aggregateErrors(schema, value) {
  const result = schema.safe(value);
  if (result.success) return result;
  
  // Parse path for field (simple; use regex for deep nests)
  const field = result.error.path.split('.')[0] || 'value';
  const errors = { [field]: result.error.message };
  
  return { success: false, errors }; // { errors: { bio: 'Too short...' } }
}

const profile = { bio: 'Hi', hobbies: [] };
const aggResult = aggregateErrors(profileSchema, profile);
console.log(aggResult); // { success: false, errors: { bio: 'Too short...', hobbies: 'Must contain at least 1 items' } }

Expected Output

• Valid: { success: true, data: { bio: '...', hobbies: ['reading'] } }.
• Invalid: { success: false, errors: { bio: 'Too short (min 5 words)', hobbies: 'Must contain at least 1 items' } }.

DX Tips

• Localization: Extend UnisafeError with i18nKey; map in catch blocks.
• Testing: Use .safe() in unit tests: expect(result.success).toBe(true).
• UI Mapping: In React, loop errors for <ErrorList /> component.
• Try It: Add to a Node script; throw/agg on bad data.

Pitfall: Deep paths (e.g., user.address.city): Use error.path to recurse.

Back to Guides

---

Last updated: October 23, 2025.