Continue M4 lib/ de-flattening with domain-agnostic infra:
- lib/hooks/: 9 pure generic hooks (useDebouncedValue, useIsMobile,
useLongPressAction, useRangeSelection, useResizeClientHeight,
useWindowVisibility, useSystemPrefersDark, useVirtualizerScrollMargin,
useRemeasureGridVirtualizer) — all PURE (only react/zustand/tanstack deps).
- lib/dnd/DragDropContext.tsx: the generic mouse-event DnD engine (WebKitGTK
HTML5-DnD workaround, ~24 importers, self-contained) — empties src/contexts/.
- lib/shortcuts/: shortcutActions + shortcutTypes (the action-id + binding
contract; registry/dispatch/bindings stay app-level and import the contract,
app->lib direction).
useWindowFullscreenState deliberately NOT moved — kept in hooks/ as app-shell
per the handoff iron-rule list (overrides its pure-helper appearance).
Pure move via deep @/lib/* specifiers. tsc 0, lint 0/0, full suite 319 files /
2353 tests green.
Move domain-agnostic, feature-free helpers out of the flat utils/ and store/
roots into src/lib/ (plan M4, §3 lib/ layer):
- lib/format/: formatBytes, formatClockTime, formatDuration, formatHumanDuration,
relativeTime (pure format/date/byte/clock helpers)
- lib/i18n.ts: i18next bootstrap (global app infra)
- lib/util/: sanitizeHtml, platform, dedupeById, safeStorage (pure helpers +
the zustand storage adapter)
playbackScheduleFormat stays in utils/format (runtime usePlayerStore dep =
audio-core coupling, not generic). formatClockTime keeps a type-only
@/store/authStoreTypes import (erased, no runtime inversion — accepted per the
deviceSync precedent).
Pure move via deep @/lib/* specifiers (no barrel → no mock-collapse surface).
tsc 0, lint 0/0, full suite 319 files / 2353 tests green.
Tooling note: lib_move.py regex extended to also rewrite side-effect imports
(import './i18n') and vi.importActual paths — both were silent gaps.
111 of 122 top-level src/utils/ files move into 16 topic folders (audio,
cache, cover, share, server, playback, playlist, deviceSync, waveform,
mix, format, export, changelog, ui, perf, componentHelpers). True
singletons with no cluster stay at the utils/ root.
Pure file-move: a path-aware codemod rewrote 539 relative-import
specifiers across 275 files; no logic touched. The hot-path coverage
gate list (.github/frontend-hot-path-files.txt) is updated to the new
paths for the 11 gated utils files — a mechanical consequence of the
move, not a CI change. tsc is green.
The 186-LOC default export shrinks to a thin window-kind switch with
shared document-attribute hooks. The mini-player tree and the main-app
tree each move into their own module under src/app/.
- src/app/MiniPlayerApp.tsx (48 LOC):
DragDropProvider + MiniPlayer + cross-window storage sync
- src/app/MainApp.tsx (129 LOC):
BrowserRouter + Routes + main-only lifecycle hooks
(audio listeners, hot cache, global shortcuts, mini-player
bridge, easter egg, scrollbar auto-hide)
AppShell + RequireAuth + TauriEventBridge are now named exports from
App.tsx so MainApp can compose them; Phase C/D will extract those into
their own modules.
App.tsx: 1453 -> 1308 LOC. Behaviour-preserving.
Psychotoxical