I’m pretty lost. I have an app that takes input from users – a subway line and a particular stop on the NYC subway. Using that, it’s supposed to output whether or not their line has a delay and how many minutes until the next train arrives. To get information on delays and train positions, I query the MTA’s public API. That querying and data manipulation all take place in one file, which I’m worried is a bit of a mess. It doesn’t work, but I’m not sure exactly what’s wrong (probably lots of things). Please go easy on me with this as I’m still somewhat of a beginner and making broken things, then fixing them, is how I learn.

Let me know if I need to add any context to this:

import GtfsRealtimeBindings from ‘gtfs-realtime-bindings’; import request from ‘request’;

function getFeedData (sub) {     var feedId;     switch (sub) {         case '1' || '2' || '3' || '4' || '5' || '6' || 'S':                 feedId = 1;                 break;             case 'A' || 'C' || 'E':                 feedId = 26;                 break;             case 'N' || 'Q' || 'R' || 'W':                 feedId = 16;                 break;             case 'B' || 'D' || 'F' || 'M':                 feedId = 21;                 break;             case 'L':                 feedId = 2;                 break;             case 'G':                 feedId = 31;                 break;     }     var requestSettings = {       method: 'GET',       uri: 'http://datamine.mta.info/mta_esi.php?key=YOUR_KEY_HERE&feed_id=2',       encoding: null     };     request(requestSettings, function (error, response, body) {       if (!error && response.statusCode == 200) {           var feed = GtfsRealtimeBindings.FeedMessage.decode(body);           return { feed: feed };         }     }); }  function reverseStop (sub, stop) {     var stopIdN     var stopIdS     var stopData = require('./stops');     var invalidEntries = 0;     function filterByName (item) {         if (item.stop_name == stop && item.stop_id.charAt(0) == sub) {             return true;         }         invalidEntries++;         return false;     }     var stopObjs = stopData.filter(filterByName);     for (var i = 0; i < stopObjs.length; i++) {         if (stopObjs[i].stop_id.charAt(stopObjs[i].stop_id.length - 1) == 'N') {             stopIdN = stopObjs[i].stop_id;         } else if (stopObjs[i].stop_id.charAt(stopObjs[i].stop_id.length - 1) == 'S') {             stopIdS = stopObjs[i].stop_id;         }     }     return {         stopIdN: stopIdN,         stopIdS: stopIdS     }; }  var isDelayN = (function (sub, stop) {     var arrivals = [];     var delays = [];     reverseStop(sub, stop);     getFeedData(sub);     (function () {             var invalidEntries = 0;             var feedObjs = getFeedData.feed.filter(function (feedObj) {                 if (feedObj.entity.trip_update.stop_time_update.stop_id  == reverseStop.stopIdN) {                     return feedObj.entity.trip_update.stop_time_update;                 }             });             for (var i = 0; i < feedObjs.length; i++) {                 arrivals.push(feedObjs.arrival.time.low);                 delays.push(feedObjs.arrival.delay);             }         })();     var nextArrival = Math.min(...arrivals);     var delayIndex = arrivals.findIndexOf(nextArrival);     var delay = delays.delayIndex;     if (delay === null || Math.ceil(delay / 60) <= 5) {         var noDelay = Math.ceil((nextArrival -  getFeedData.feed.header.timestamp.low) / 60);         return { noDelay: noDelay };     } else {         var yesDelay = Math.ceil(delay / 60);         return { yesDelay: yesDelay };     } })();  var isDelayS = (function (sub, stop) {     var arrivals = [];     var delays = [];     reverseStop(stop);     getFeedData(sub)         .then(function (feed) {             var invalidEntries = 0;             var feedObjs = feed.filter(function (feedObj) {                 if (feedObj.entity.trip_update.stop_time_update.stop_id  == reverseStop.stopIdS) {                     return feedObj.entity.trip_update.stop_time_update;                 }             });             for (var i = 0; i < feedObjs; i++) {                 arrivals.push(feedObjs.arrival.time.low);                 delays.push(feedObjs.arrival.delay);             }         });     var nextArrival = Math.min(...arrivals);     var delayInex = arrivals.findIndexOf(nextArrival);     var delay = delays.delayIndex;     if (delay === null || Math.ceil(delay / 60) <= 5) {         var noDelay = Math.ceil((nextArrival -  getFeedData.feed.header.timestamp.low) / 60);         return { noDelay: noDelay };     } else {         var yesDelay = Math.ceil(delay / 60);         return { yesDelay: yesDelay };     } })();  export { isDelayN, isDelayS };