slow-zone/lib/presenters/train.js

A client & wrapper for CTA 'L' arrival data.

const Dateline = require("dateline");

const STRING_FIELDS = {
  destNm: "destinationName",
  rt: "routeId",
  staNm: "stationName",
  stpDe: "stopDescription"
};

// Helpers
const getNativeBoolean = booleanString => getNativeInteger(booleanString) === 1;

const getNativeDate = timeString => {
  var day, hour, min, month, sec, str, year;
  [str, year, month, day, hour, min, sec] = timeString.match(
    /(\d{4})(\d{2})(\d{2}) (\d{2}):(\d{2}):(\d{2})/
  );
  return new Date(year, month - 1, day, hour, min, sec);
};

const getNativeFloat = floatString => parseFloat(floatString);

const getNativeInteger = integerString => parseInt(integerString, 10);

class Train {
  constructor(attributes = {}) {
    var attributeName, methodName;
    this.attributes = attributes;
    // Map string fields that don't need additional processing
    for (attributeName in STRING_FIELDS) {
      methodName = STRING_FIELDS[attributeName];
      this[methodName] = (function(value) {
        return function() {
          return value;
        };
      })(this.attributes[attributeName]);
    }
  }

  // Boolean Fields
  isApproaching() {
    return getNativeBoolean(this.attributes.isApp);
  }

  isDelayed() {
    return getNativeBoolean(this.attributes.isDly);
  }

  isFaulty() {
    return getNativeBoolean(this.attributes.isFlt);
  }

  isScheduled() {
    return getNativeBoolean(this.attributes.isSch);
  }

  // Date Fields
  arrivalTime() {
    return getNativeDate(this.attributes.arrT);
  }

  predictionTime() {
    return getNativeDate(this.attributes.prdt);
  }

  // Floating Point Fields
  latitude() {
    return getNativeFloat(this.attributes.lat);
  }

  longitude() {
    return getNativeFloat(this.attributes.lon);
  }

  // Generated Fields
  arrivalMinutes() {
    return Math.round(
      (this.arrivalTime() - this.predictionTime()) / (60 * 1000)
    );
  }

  arrivalString() {
    return Dateline(this.arrivalTime()).getAPTime();
  }

  predictionAge() {
    return Math.round((new Date() - this.predictionTime()) / 1000);
  }

  route() {
    var route;
    switch ((route = this.routeId())) {
      case "Brn":
        return "Brown";
      case "G":
        return "Green";
      case "Org":
        return "Orange";
      case "P":
        return "Purple";
      case "Y":
        return "Yellow";
      default:
        return route;
    }
  }

  routeClass() {
    return this.route().toLowerCase();
  }

  // Integer Fields
  destinationId() {
    return getNativeInteger(this.attributes.destSt);
  }

  directionId() {
    return getNativeInteger(this.attributes.trDr);
  }

  heading() {
    return getNativeInteger(this.attributes.heading);
  }

  runNumber() {
    return getNativeInteger(this.attributes.rn);
  }

  stationId() {
    return getNativeInteger(this.attributes.staId);
  }

  stopId() {
    return getNativeInteger(this.attributes.stpId);
  }

  toHash() {
    return {
      destination: {
        id: this.destinationId(),
        name: this.destinationName()
      },
      location: {
        latitude: this.latitude(),
        longitude: this.longitude(),
        heading: this.heading()
      },
      prediction: {
        arrivalMinutes: this.arrivalMinutes(),
        arrivalString: this.arrivalString(),
        arrivalTime: this.arrivalTime(),
        predictionAge: this.predictionAge(),
        predictionTime: this.predictionTime()
      },
      route: {
        class: this.routeClass(),
        directionId: this.directionId(),
        id: this.routeId(),
        name: this.route(),
        run: this.runNumber()
      },
      station: {
        id: this.stationId(),
        name: this.stationName(),
        stop: {
          id: this.stopId(),
          description: this.stopDescription()
        }
      },
      status: {
        approaching: this.isApproaching(),
        delayed: this.isDelayed(),
        faulty: this.isFaulty(),
        scheduled: this.isScheduled()
      }
    };
  }
}

module.exports = Train;