Use Node.js 24 and the repository's pnpm lockfile. During development/review, select affected Vitest files (for example pnpm exec vitest run src/components/files-browser.test.ts) and run pnpm typecheck; add the relevant style/lint, build or browser checks when those boundaries change. pnpm check runs all formatting, lint, tests, type checking and the production build for final integration/release. The check-scope policy owns evidence reuse.

DOM-free tests declare // @vitest-environment node. Shared setup loads browser helpers only in jsdom. Component tests and benchmarks retain jsdom; tests default to two workers.

Shared file browser

YATM consumes the published @samuelncui/chonky and @samuelncui/chonky-icon-fontawesome 0.3.6 packages. The lockfile resolves the registry artifacts directly; no local checkout or dependency patch is required. See the Chonky component documentation.

Shared row presentation, grouping, selection, keyboard handling, drag/drop, breadcrumbs and browser footers belong in Chonky. YATM supplies queries, pagination, metadata, operation capabilities and action handlers through its supported interfaces. Group layout actions belong to the caller's Options menu.

Consumer regression tests cover file status, measured rows, loading/navigation, drag/drop, selection waitlists and the independent identical-file tool. Keep these tests when upgrading the published dependency.

Packaged browser acceptance

pnpm test:e2e runs Chromium against an already running, isolated Demo server. Install the browser once with pnpm exec playwright install chromium. Set YATM_BROWSER_URL to its loopback URL (an SSH tunnel is also supported), and YATM_BROWSER_COMMIT to the expected packaged commit. The tests verify the page's embedded identity, exercise both file panes and Identical sorting, random scrolling, hidden files, collapse and selection, and delete two disposable Demo files while holding the first response. They assert that these interactions do not start another global Find. Do not point this mutating suite at a normal installation.

The E2E guide owns fixture and server setup. Traces and failure screenshots go to output/browser-results. These checks complement unit tests of request interleavings and the backend's large-data checks; they do not replace physical Media acceptance.

Frontend benchmarks

Run pnpm bench separately from other builds and tests. The single case in files-browser.bench.ts measures production directory projection/accumulation for 10,000 entries in 500-row streamed batches.

It uses Vitest's iteration loop with a 50 ms warmup and 250 ms measurement budget, completing at least one operation per phase. Fixture construction is outside measurement; mock replies and final-result assertions are inside. This is a CPU-oriented elapsed timing in Node/jsdom with immediate mocked RPC replies. It does not measure network/server work, full Files-pane stream publication, Identical updates, Chonky rendering, browser paint, frame rate or scrolling latency. Existing Identical structural and UI tests, and Chonky browser checks, retain their correctness and layout coverage.

For comparison, run the comparison runner from the repository root, separately from other builds, tests and measurements. Supply three Git checkout roots and a new output directory outside all three checkouts; its parent must already exist. The harness checkout supplies the common benchmark file above. Use the current Node.js >=24 and pnpm on one machine:

node frontend/scripts/compare-performance.mjs \
  --baseline "$PERF_BASELINE" --candidate "$PERF_CANDIDATE" \
  --harness "$PERF_HARNESS" --out "$PERF_OUTPUT"

The runner copies current tracked frontend/ files, including tracked edits and deletions, into disposable directories. It excludes untracked/ignored files, existing dependencies and Git metadata, and rejects symlinks and tracked private environment or registry configuration. Stage new source files before comparing. Both copies receive the same tracked benchmark file; each retains its own implementation, test helpers, Vitest configuration and dependency lockfile. Supplied checkouts remain unchanged.

Both copies finish pnpm install --frozen-lockfile using the public npm registry before measurement, with disposable home, configuration, cache and store directories. Both sides use one recorded pnpm version; project package-manager switching is disabled. The runner checks that both copies use its Node executable and that their lockfiles remain unchanged. Each then runs pnpm exec vitest bench --run --maxWorkers=1 for this case exactly once: baseline with --outputJson, then candidate with --compare and --outputJson. No bench package script is required in either source.

Output contains pair.json with source commits and tracked-file hashes, lockfile and harness hashes, runner/tool identities, environment facts, commands and completion status. Source hashes describe the files before the common harness overlay. Any native baseline.json and candidate.json results and install/benchmark logs produced before a failure are retained; disposable copies are removed when the runner exits normally or reports an error. Missing, invalid or unmatched measurements fail the command and leave complete: false.

Vitest reports the comparison without a custom sampling loop or regression gate. A single short run can be noisy; its timing report complements semantic tests and is not browser performance acceptance. pnpm check does not run these opt-in benchmarks. Run the tooling tests separately without installing dependencies or measuring performance:

node --test frontend/scripts/compare-performance.test.mjs

Inline feedback

Use Feedback for inline errors and any Alert with actions; put controls in its action slot. It owns message wrapping, icon/action alignment, responsive placement and surrounding space. Callers retain their existing retry and cancellation behavior. The lint rule rejects direct MUI error Alerts and Alerts with controls outside this component. Use the shared errorMessage formatter for failures; it decodes RPC status text once and preserves ordinary errors and malformed wire text without throwing.

State and styles

The UI architecture owns shared state, preference persistence, styling boundaries and initialization order. Use the application Redux hooks for shared selections, committed Settings and Jobs return snapshots; keep form drafts and request lifetimes with their views.

Run pnpm styles:check for known style-boundary violations and pnpm lint for component usage rules. Include browser checks of loading/disabled states, portals, nested browsers and narrow layouts when changing shared presentation.