loopr

Repeat any GPX loop into a longer ride.

Drop a .gpx of one lap, pick how many times to ride it (or a target distance), download a stitched GPX you can import into Strava, Ride With GPS, Garmin Connect, or Wahoo. Everything happens in the browser — your file never leaves your device.

Live at loopr.willcsoftware.com.

What it does

• Parse GPX (multi-segment, multi-track, with routes and waypoints).
• Repeat each <trk> N times with the seam deduped between laps.
• Optionally drop a waypoint at the start of each lap so your bike computer can show them.
• Strip <time> (this isn't a ride — it's a plan).
• Compute distance, elevation gain/loss, and max gradient over a 100m moving window for a live summary.
• Emit valid GPX 1.1 with creator="loopr <version>".

Stack

• SvelteKit + Svelte 5 (runes), TypeScript strict
• @sveltejs/adapter-static → GitHub Pages
• Vitest + Playwright
• pnpm

Develop

corepack enable
pnpm install
pnpm dev

Verify

pnpm check        # svelte-check + tsc
pnpm test:unit    # vitest, GPX library
pnpm test:e2e     # functional, accessibility, responsive, and visual browser suite
pnpm test:e2e:functional # all browser checks except screenshot comparisons
pnpm test:visual  # compare committed screenshots across desktop and mobile browsers
pnpm validate     # complete pre-push check: types, lint, unit, UI, and visual tests
pnpm build        # static output → build/
pnpm preview      # serves build/ at :4173

The UI contract runs in desktop Chromium, Firefox, and WebKit, plus Pixel/Chrome and iPhone/WebKit profiles. WebKit is the repeatable CI proxy for Safari. Before changing the UI intentionally, refresh and inspect baselines on macOS with pnpm test:visual:update, then commit the images under tests/e2e/__screenshots__. CI compares them on the macOS 26 arm64 runner to minimize platform-specific rendering differences from local Apple Silicon Macs.

Playwright's WebKit build is not the exact Safari binary shipped by macOS. For a release-level Safari check, run the suite locally on macOS and do a short manual pass in the current Safari; CI still catches the large majority of WebKit-specific layout and behavior regressions on every PR.

MIT, © 2026 WillC Software House.