growstuff/app/assets/javascripts/places.js.erb

if (document.getElementById("placesmap") !== null) {
  places_base_path = "/places";
  mapbox_map_id = "<%= Rails.env == 'test' ? 0 : Growstuff::Application.config.mapbox_map_id %>";
  mapbox_base_url = "https://c.tiles.mapbox.com/v3/" + mapbox_map_id + "/{z}/{x}/{y}.png";
  nominatim_base_url = 'http://nominatim.openstreetmap.org/search/';
  nominatim_user_agent_email = "<%= Rails.env == 'test' ? 0 : Growstuff::Application.config.user_agent_email %>";

  L.Icon.Default.imagePath = '/assets'

  if (location.pathname === places_base_path) { //places index page
    placesmap = L.map('placesmap').setView([0.0, -0.0], 2);
    showMap(placesmap);
  } else { // specific place page
    place = location.pathname.replace(places_base_path + "/", '');
    nominatim_query_url = nominatim_base_url + place;
    nominatim_options = {
      format: "json",
      callback: "placeholder",
      limit: 1,
      email: nominatim_user_agent_email
    };
    $.getJSON(nominatim_query_url, nominatim_options, function(data) {
      placesmap = L.map('placesmap').setView([data[0].lat, data[0].lon], 5);
      showMap(placesmap);
    })
  }
}

function showMap(placesmap) {
  L.tileLayer(mapbox_base_url, {
    attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors under <a href="http://www.openstreetmap.org/copyright">ODbL</a> | Map imagery &copy; <a href="http://mapbox.com">Mapbox</a>',
    maxZoom: 18
  }).addTo(placesmap);
  markers = new L.MarkerClusterGroup({showCoverageOnHover: false, maxClusterRadius: 20 });

  things_to_map = location.pathname + '.json';
  $.getJSON(things_to_map, function(members) {
    $.each(members, function(i, m) {
      if (m.latitude && m.longitude) {
        marker = new L.Marker(new L.LatLng(m.latitude, m.longitude));
        link = "<p><a href='/members/" + m.slug + "'>" + m.login_name + "</a></p>";
        where = "<p><i>" + m.location + "</i></p>";
        marker.bindPopup(link + where).openPopup();
        markers.addLayer(marker);
      }
    });
  });

  placesmap.addLayer(markers);
}