MTA commute

Phone pages that plan subway commutes from the MTA's real-time feeds, directly from the browser (no API key, no server). Each route has its own page:

• hoyt-to-51st.html: Hoyt-Schermerhorn → 51 St, by A/C, 4/5 at Fulton St, and 6 at Grand Central.
• union-sq-to-51st.html: Union Sq → 51 St, by the 6 direct or 4/5 with a change to the 6 at Grand Central.
• 51st-lex-to-hoyt.html: 51 St or Lexington Av-53 St → Hoyt-Schermerhorn, by 6, 4/5 at Grand Central, and A/C at Fulton St, by 6, F at Broadway-Lafayette, and A/C at Jay St, or by E/F to Court Sq and the G.
• hoyt-to-14st.html: Hoyt-Schermerhorn → 14 St (F/M), by A/C and then F at Jay St or F/M at W 4 St.
• 14st-to-hoyt.html: 14 St (F/M) → Hoyt-Schermerhorn, the same in reverse.

index.html links to all of them.

How it is built:

• routes.js describes each route: its legs, its transfers, which feeds to read, and its default mode. "Arrive between" picks the shortest trip that arrives inside a window. "Leave now" picks the soonest arrival.
• app.js builds and runs a route page. It refreshes every 20 seconds while open, and never more than once every 15 seconds.
• planner.js decodes GTFS-realtime and finds the best connection for each train.
• schedule.json is the timetable for the stops in routes.js. The page uses it for trains that the live feed has not published yet, because the feed lists a train only about 40 minutes ahead. .github/workflows/schedule.yml rebuilds it every day from the MTA's supplemented GTFS with build_schedule.py.
• sw.js keeps the pages on the phone, so they open with no signal.