Web Storage & Offline
Beyond localStorage. IndexedDB for structured data at scale, Cache API for offline-first strategies, OPFS for high-performance file access, storage quotas and eviction, and the sync patterns that make apps work without a network and reconcile gracefully when it returns.
A complete map of every browser storage API — localStorage, sessionStorage, IndexedDB, Cache API, OPFS, and cookies. Understand their storage limits, performance characteristics, when to use each, and how browsers manage quotas and eviction.
Master IndexedDB from the ground up — database versioning, object stores, transactions, indexes, cursor patterns, key ranges, and performance optimization. Learn to build production-grade client-side data layers that handle millions of records without blocking the main thread.
Master the Cache API and service worker lifecycle for building offline-capable web apps. Learn cache-first, network-first, stale-while-revalidate, and other caching strategies. Understand service worker installation, activation, fetch interception, and cache versioning.
Deep dive into OPFS — the browser's fastest storage API. Learn the async and sync access patterns, Worker-based file I/O, performance advantages over IndexedDB, SQLite WASM integration, and practical patterns for high-performance client-side data processing.
Build apps that work without a network and reconcile gracefully when connectivity returns. Master offline-first architecture, conflict resolution strategies, Background Sync API, optimistic UI, operation queues, and the basics of CRDTs for automatic conflict-free merging.