Coding the happy path with Commands and Exceptions
summary
A Flutter app called Watch Crunch uses Thomas Burkhart’s packages (get_it, fl_command, watch_it) to move error, busy and result handling out of widgets: a Command wraps async work, exposes errors ValueListenable, isExecuting and a canExecute restrictions input, catches exceptions to a global handler with pluggable filters, and prevents double execution. Implementations include a paged FeedDataSource, a global post repository with change‑notifier proxies, optimistic updates with an undoable command and executeWithFuture for pull‑to‑refresh — all running in production.
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chapters (14)
- 0:00Introduction and motivation
- 2:10Happy path vs error handling
- 4:17What are Flutter Commands
- 8:54Command features and use cases
- 11:10Error handling with Commands
- 13:36Real-world error filter example
- 16:50UI integration with WatchIt
- 19:47Paginated feed data sources
- 26:10Mutable data and change notifiers
- 28:17Post proxy and repository pattern
- 31:30User proxy and data abstraction
- 34:44Optimistic UI updates
- 36:33Undoable Commands
- 38:41Conclusion and resources
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