Flutter

Scope

• In scope: Flutter mobile UI performance, widget tree design, state locality, and architecture boundaries between presentation/domain/data.
• Out of scope: platform-specific native code internals and non-Flutter mobile stacks.

Invariants

• Keep build() cheap and deterministic; split large widgets into focused subwidgets.
• Localize state updates to the smallest subtree that needs repainting.
• Separate UI, domain logic, and data access into clear layers.
• Prefer immutable models and explicit state transitions for predictable rendering.
• Validate performance decisions with tooling (DevTools/profile mode), not assumptions.

Validation Checklist

• Use official guidance for implementation decisions:
  • https://docs.flutter.dev/perf/best-practices
  • https://docs.flutter.dev/app-architecture/recommendations
• Run formatting/lints/tests required by the project and resolve warnings.
• Profile key flows in DevTools when touching render-heavy screens.
• Verify no jank regressions on critical navigation or list interactions.

Failure Handling

• If frame drops appear after a change, stop and identify repaint/rebuild hotspots before adding complexity.
• If state logic leaks across layers, refactor to restore clear presentation/domain/data boundaries.
• If architecture trade-offs are uncertain, choose the simplest layered option and document the decision.

High-Value Flutter Practices

• Use const constructors/widgets whenever possible to reduce rebuild cost.
• Avoid broad setState calls at page roots; isolate updates in leaf widgets.
• Keep async side effects out of widgets when feasible; delegate to controllers/notifiers.
• Prefer composition over deep inheritance for reusable UI behavior.

Source: theCat69/la-briguade — distributed by TomeVault.