Browser Data Rescue — eight failure drills and runnable companion

By Shruti. A compact original workbook for developers of browser-local applications. Approximately 3,600 words, 11 printable PDF pages, a reflowable EPUB, eight original diagrams and runnable synthetic companion source.

Practice eight failure boundaries: premature saved acknowledgment; blocked upgrades; failed-write draft preservation; external backup recovery; invalid input; stale-tab revision conflicts; cache versus user data; and conditional retention decisions. Includes exercises and failing/fixed code review notes.

Requires basic JavaScript and localhost/HTTPS for companion use. These are bounded teaching drills, not a utility that recovers arbitrary production data. Injected failures are labeled; actual quota exhaustion, eviction, Safari/private-mode and power-loss behavior are not verified. No API subscription required.

Single-purchaser license allows adapting source for your own commercial projects; no resale of the book or kit. Free reference labs retain their separate MIT license. Check the included README and test notes before use.