kPreviewEnabled top-level constant

bool const kPreviewEnabled

Compile-time switch for the preview catalog.

Defaults to kDebugMode: ON in debug builds, OFF in profile and release (kDebugMode is false in both). A profile build can opt in with --dart-define=PREVIEW_ENABLED=true; a debug build can force it off with --dart-define=PREVIEW_ENABLED=false. Release is always blocked by the kReleaseMode guard in MagicPreview.registerRoutes regardless. Because this is a const, the release-mode optimizer can fold the guarded branch in MagicPreview.registerRoutes dead and tree-shake the entire catalog, every PreviewEntry, and every builder it transitively references. release-mode optimizer can fold the guarded branch in MagicPreview.registerRoutes dead and tree-shake the entire catalog, every PreviewEntry, and every builder it transitively references.

Implementation

const bool kPreviewEnabled = bool.fromEnvironment(
  'PREVIEW_ENABLED',
  defaultValue: kDebugMode,
);