Custom Axioms

Creating and using custom axioms (Email, Currency, Status, Priority) for domain-specific requirements

const customerWithCustomFields = {
id: 'cust-123',
type: 'customer',
version: 3,
createdAt: new Date('2024-01-15T10:30:00Z'),
updatedAt: new Date('2024-01-20T14:45:00Z'),
email: 'alice@example.com',
status: 'active',
priority: 3,
profile: {
  name: 'Alice Johnson',
  phone: '+1-555-0123',
},
preferences: {
  currency: 'USD',
  language: 'en',
},
}

const _productWithCustomFields = {
id: 'prod-456',
type: 'product',
version: 7,
createdAt: new Date('2024-01-10T09:00:00Z'),
updatedAt: new Date('2024-01-25T16:20:00Z'),
name: 'Canon Framework License',
price: 99.99, // Will be converted to currency
currency: 'USD',
status: 'active',
priority: 2, // Numeric priority
category: 'software',
createdBy: 'admin-789',
}

const orderWithCustomFields = {
id: 'order-789',
type: 'order',
version: 2,
createdAt: new Date('2024-01-15T09:30:00Z'),
updatedAt: new Date('2024-01-15T11:45:00Z'),
status: 'active',
priority: { level: 2, label: 'medium' },
total: '$199.98', // Currency string
currency: 'USD',
customerId: 'cust-123',
items: [
  {
    productId: 'prod-456',
    quantity: 2,
    price: 99.99,
  },
],
}

extracts email from customer entity:

const email = emailOf(customerWithCustomFields)
expect(email).toBe('alice@example.com')

validates email format:

const invalidCustomer = { ...customerWithCustomFields, email: 'invalid-email' }
expect(() => emailOf(invalidCustomer)).toThrow('Invalid email format')

converts currency from different formats:

// Test number conversion
const currency1 = currencyOf(99.99)
expect(currency1).toEqual({ amount: 99.99, currency: 'USD' })

// Test string conversion
const currency2 = currencyOf('$150.50 USD')
expect(currency2).toEqual({ amount: 150.5, currency: 'USD' })

// Test object (already canonical)
const currency3 = currencyOf({ amount: 200, currency: 'EUR' })
expect(currency3).toEqual({ amount: 200, currency: 'EUR' })

extracts and validates status:

const status = statusOf(customerWithCustomFields)
expect(status).toBe('active')

validates status transitions:

const invalidStatus = { ...customerWithCustomFields, status: 'invalid' }
expect(() => statusOf(invalidStatus)).toThrow('Invalid status')

converts priority from different formats:

// Test string conversion
const priority1 = priorityOf('high')
expect(priority1).toEqual({ level: 3, label: 'high' })

// Test number conversion
const priority2 = priorityOf(2)
expect(priority2).toEqual({ level: 2, label: 'medium' })

// Test object (already canonical)
const priority3 = priorityOf({ level: 4, label: 'critical' })
expect(priority3).toEqual({ level: 4, label: 'critical' })

processes customer registration with custom validation:

const result = processCustomerRegistration(customerWithCustomFields)

expect(result.success).toBe(true)
expect(result.customerId).toBe('cust-123')
expect(result.email).toBe('alice@example.com')
expect(result.status).toBe('active')
expect(result.priority.level).toBe(3)

calculates order total with currency conversion:

const result = calculateOrderTotalWithCurrency(orderWithCustomFields)

expect(result.subtotal.amount).toBe(199.98)
expect(result.tax.amount).toBeCloseTo(15.998, 2)
expect(result.total.amount).toBeCloseTo(215.978, 2)
expect(result.subtotal.currency).toBe('USD')

validates status transitions:

const result = updateEntityStatus(customerWithCustomFields, 'inactive')

expect(result.success).toBe(true)
expect(result.oldStatus).toBe('active')
expect(result.newStatus).toBe('inactive')

rejects invalid status transitions:

const result = updateEntityStatus(customerWithCustomFields, 'draft')

expect(result.success).toBe(false)
expect(result.error).toContain('Invalid transition')

---

References

Source: View on GitHub

Metadata

Keywords: custom-axioms, domain-specific, email, currency, status, priority Difficulty: advanced