YouBike Locator

Locate the nearest YouBike without having to visit YouBike's website or app.

Open the page, allow location access, and it shows the closest station that actually has a bike to rent — with distance, walking time, a live count split into regular and electric bikes, free docks, and a one-tap link to directions.

The regular/electric split matters: about half of all stations hold both models at once, so a single "bikes" number does not tell you whether you are getting a pedal bike or an e-bike.

How it works

YouBike publishes a single public JSON feed of every station in Taiwan (~9,500 stations, ~6 MB). Shipping that to the browser on each visit would be wasteful, so the feed never leaves the server:

• src/lib/stations.ts (server-only) fetches the feed and keeps it in an in-process cache with a 60-second TTL, matching how often YouBike refreshes. Concurrent requests share one in-flight fetch, and a failed refresh falls back to the last good snapshot rather than erroring.
• src/app/api/nearest/route.ts takes lat and lng, does the distance maths server-side, and returns only the handful of stations that matter (~1.5 KB).
• src/app/page.tsx is the client component: it asks for the browser's location, calls that endpoint, and renders the result.

The feed is deliberately kept out of the Next.js data cache, whose per-entry size limit a 6 MB payload comfortably exceeds.

Getting started

npm install
npm run dev

Open http://localhost:3000.

Location services require a secure context: localhost works, but any other host needs HTTPS.

Configuration

No environment variables are required. YOUBIKE_API can optionally override the feed URL — see .env.example.

Scripts

Command	Purpose
npm run dev	Development server
npm run build	Production build
npm run start	Serve the production build
npm run lint	ESLint

Deploying

The app is a stock Next.js project with no external services, so vercel --prod (or connecting the repo on Vercel) is all that is needed.