app.js

var locations = require('./locations');
var haversine = require('haversine');
var _ = require('lodash');

var find = exports.find = _.partial(_.find, locations);
var filter = exports.filter = _.partial(_.filter, locations);

exports.zip_lookup = exports.zipLookup = function(zipcode) {
  zipcode = _.padStart(zipcode, 5, 0);
  return find({
    zipcode: zipcode
  });
};

exports.gps_lookup = exports.gpsLookup = function(latitude, longitude) {
  var minDistance = Infinity; // simulate infinity
  var minLocation = {};

  var start = {
    latitude: latitude,
    longitude: longitude
  }

  for (var i = 0; i < locations.length; i++) {
    var distance = haversine(start, locations[i]);

    if (distance < minDistance) {
      minLocation = locations[i];
      minDistance = distance;
    }
  }

  minLocation.distance = minDistance;
  return minLocation;
};

exports.findByState = function(state) {
  state = state.toUpperCase()
  return filter({
    state_abbr: state
  })
}

exports.findByCityAndState = function(city, state) {
  state = state.toUpperCase()
  city = city.toUpperCase()

  var cities = filter({
    state_abbr: state
  })
  return _.find(cities, function(c) {
    return c.city.toUpperCase() === city
  })
}