Provides idempotency guarantees for mutation endpoints by storing response keys and returning cached results for duplicate requests. Uses configurable storage backend (e.g., Map, Redis) and a cleanup job. Extracted and reusable in any NestJS API that requires idempotent mutation handling.

Manages a queue of offline mutations (create, update, delete) that are applied when connectivity is restored. Supports conflict detection via `_rev` timestamps, retry with exponential backoff, and rollback on failure. Isolated pattern suitable for any offline-first application with synchronous local cache and async server sync.

Encapsulates file storage behind a common interface with drivers for local filesystem, S3-compatible object stores, and a mirror driver. Handles key validation, path prefixing, content-type detection, and streaming. Testable via contract tests that run against any driver. Can be extracted as a standalone storage library.

Generates SVG markup for Lucide icons without requiring React or jsdom, enabling server-side or client-side rendering of icon sprites. Maintains byte-identical output to react-dom/server for all icons via parity tests. Useful for any project needing lightweight icon serialization outside the React render tree.

Sets up a Dexie IndexedDB database with typed tables for storing trip data locally. Includes schema versioning, composite indexes for efficient queries, and lifecycle management. Extracted as a single file that can be used in any offline-capable web app requiring local persistence.

Manages concurrent file uploads with a configurable concurrency limit, retry logic for transient failures, progress tracking, and cancellation via AbortController. Handles non-retryable errors (e.g., 413, 403) by failing immediately. Reusable in any web app that needs robust client-side file upload with backpressure.