feat(ScheduleFinderLive): show in-seat transfers

[thecristen]

Scope

Just testing out this idea...

Implementation

Yesterday I wrote a library to pull in and update GTFS data.
Then here I wrote a helper function to access the relevant rows from transfers.txt.
Then I updated the departures page, to be able to show you the extra stops you can reach if you stay aboard.

Some choices made:

• Didn't show this for ferries, because the loop is too weird. Is this too extreme of a take?
• Shows a special "Continues on" message with the route for the next trip. Only if the route actually changes. This mostly seems to impact the SL1, so that we don't show "Continues on SL1" when it switches trip/direction at Terminal A.
• Caps extra trips at a total number of 4, which is enough to accommodate known chains on in-seat transfers, I think

Bonus: I am trying out position: sticky to keep the route+headsign in view when you scroll down the list of schedules:

Screenshots

57.mov

How to test

In transfers.txt we can see the trips which come into play, so we can look up those trips and find departures pages to test. I've been enjoying these:

• http://localhost:4001/departures?route_id=57&direction_id=1&stop_id=917
• http://localhost:4001/departures?route_id=741&direction_id=0&stop_id=place-crtst
• http://localhost:4001/departures?route_id=Boat-F10&direction_id=0&stop_id=Boat-Aquarium
• http://localhost:4001/departures?route_id=37&direction_id=1&stop_id=11839

(for the 37/57 and maybe others, you'll have to select the weekday service that's not yet active -- because the trips of concern happen when school is in session).

TODO: I need to add tests here.