slow-zone/lib/index.js

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

const {extend, isArray, map} = require("underscore");
const request = require("request");
const xml2js = require("xml2js");

const Train = require("./presenters/train");
const xmlParser = new xml2js.Parser({explicitArray: false});

class SlowZone {
  constructor(options) {
    var i, len, namespace, ref;
    this.baseUrl = "http://lapi.transitchicago.com/api/1.0";
    this.apiKey = options.apiKey;
    ref = ["arrivals", "follow"];
    for (i = 0, len = ref.length; i < len; i++) {
      namespace = ref[i];
      this.registerEndpoints(namespace);
    }
  }

  registerEndpoints(namespace) {
    const endpoint = require(`./endpoints/${namespace}`)(this);
    return extend(this, endpoint);
  }

  fetch(endpoint, queryParams, callback) {
    const defaultQueryParams = {
      key: this.apiKey
    };

    const apiOptions = {
      qs: extend({}, queryParams, defaultQueryParams),
      uri: `${this.baseUrl}/${endpoint}`
    };

    request(apiOptions, function(err, res, body) {
      if (err != null) {
        return callback(err);
      }

      xmlParser.parseString(body, (err, result) => {
        var ref, ref1, trainData;

        if (
          (result != null
            ? (ref = result.ctatt) != null ? ref.errCd : void 0
            : void 0) !== "0"
        ) {
          return callback(
            new Error(`${result.ctatt.errCd} – ${result.ctatt.errNm}`)
          );
        }

        const predictions = (ref1 = result.ctatt) != null ? ref1.eta : void 0;

        if (!predictions) {
          return callback(err, []);
        }

        if (!isArray(predictions)) {
          predictions = [predictions];
        }

        const response = (function() {
          var i, len, results;
          results = [];
          for (i = 0, len = predictions.length; i < len; i++) {
            trainData = predictions[i];
            results.push(new Train(trainData).toHash());
          }
          return results;
        })();

        callback(err, response);
      });
    });
  }
}

module.exports = SlowZone;