dinero-currency-patterns

# Dinero.js Currency Patterns Patterns for handling currencies with [Dinero.js](https://v2.dinerojs.com): type safety, conversions, custom currencies, database storage, and payment service integration. ## When to Apply Reference these guidelines when: - Converting between currencies with `convert` - Defining custom currencies (e.g., cryptocurrencies, loyalty points) - Looking up currencies dynamically from external input - Storing monetary values in a database - Integrating with payment services (Stripe, PayPal, Square) ## Rule Categories by Priority | Priority | Category | Impact | Prefix | | -------- | ------------------- | ------ | ---------- | | 1 | Type Safety | HIGH | `types-` | | 2 | Conversion | HIGH | `convert-` | | 3 | Storage | HIGH | `storage-` | | 4 | Payment Integration | MEDIUM | `payment-` | ## Quick Reference ### 1. Type Safety (HIGH) - `types-as-const` - Define custom currencies with `as const satisfies` for compile-time safety - `types-currency-mismatch` - TypeScript catches currency mismatches in operations at compile time - `types-lookup-validation` - Validate currency codes from external sources at runtime ### 2. Conversion (HIGH) - `convert-scaled-rates` - Use scaled amounts for fractional exchange rates, not floats - `convert-reusable` - Build reusable converter functions with higher-order patterns ### 3. Storage (HIGH) - `storage-database` - Store amount, currency code, and scale as separate columns - `storage-no-money-type` - Avoid PostgreSQL's `money` type for multi-currency applications ### 4. Payment Integration (MEDIUM) - `payment-services` - Map Dinero objects to payment service formats with dedicated helpers ## How to Use Read individual rule files for detailed explanations and code examples: ``` rules/types-as-const.md rules/convert-scaled-rates.md ``` Each rule file contains: - Brief explanation of why it matters - Incorrect code example with explanation - Correct code example with explanation - Additional context and references