A complete, modular email template generation system. It provides a base template structure with header/body/footer, formatters for dates and times, and specific templates for booking confirmation, cancellation, reschedule, reminders, and admin notifications. Each template is a pure function that takes typed data and returns HTML. The system is isolated (only depends on types and formatters within the same module) and could be extracted into a standalone package for any application needing transactional email generation.

A multi-tier caching layer designed for Cloudflare serverless environments. It includes a KV cache wrapper with TTL-based expiration, a browser cache using localStorage with memory fallback, cache strategy definitions for different data types (availability, calendar, bookings), and a lock-based mechanism to prevent cache stampedes during concurrent requests. The abstraction is clean and could be reused in other Cloudflare-based projects.

A utility for coalescing identical in-flight requests and batching multiple operations into a single call. It prevents duplicate concurrent requests for the same resource and allows grouping of items (e.g., multiple date availability checks) into a batch that is processed after a short delay. The pattern is generic and can be extracted for any async system to reduce redundant network calls.