Working with Google Maps, Stamen Tiles (an existing tile library) and Require.js?

Question

I am trying to write a module`to load a Stamen tile map under Require.js, but I'm unsure how to best use it with Require.

If you haven't seen Stamen maps before, their site is at Stamen Maps .

This is the code for the map view, view.js

define([
  'jquery',
  'underscore',
  'backbone',
  'maps',
  'text!templates/map/view.html'
], function($, _, Backbone, maps, mapTemplate){
  var mapView = Backbone.View.extend({
    el: $(".map"),
    displayMap: function() {
      this.options = {
        center: new maps.LatLng(-37.8, 144.9),
        zoom: 11,
        mapTypeId: google.maps.MapTypeId.ROADMAP,
        scrollwheel: false
      };
      this.render();
    },
    render: function(){
      var compiledTemplate = _.template(mapTemplate);
      var $el = $(this.el);
      $el.html(compiledTemplate);
      this.map = new maps.Map($el.find('.map').get(0), this.options);
    }
  });
  return new mapView;
});

I am loading the maps API following modules:

map.js

define(['google!maps/3/sensor=false'], function() { 
  return google.maps;
});

Which has the dependency of google.js

define(['http://www.google.com/jsapi?key=THE_API_KEY&callback=define'], { 
  load: function( name, req, load, config ) { 
    if (config.isBuild) {
      onLoad(null);
    } else {
      var request = name.split('/'); 
      google.load(request[0], request[1], { 
        callback: load, 
        language: 'en', 
        other_params: ((typeof request[2] === 'string')?request[2]:'') 
      });
    }
  } 
});

The issue is that the Stamen maps layers appear to edit the Google Maps instance directly. You can see the Stamen maps implementation here: http://maps.stamen.com/js/tile.stamen.js?v1.1.1

google.maps.StamenMapType = function(name) {
  //Implementation
}

It seems to rely on the global google.maps object, which is where I believe the issue is coming from.

I'm unsure how to best rewrite the Stamen plugin to be require.js friendly, or if I need to, and I am really keen on using it. Unless I take Google Maps and Stamen out of Require.js and load them normally (like I do with Modernizr) but I'd much prefer to try and do it the Require.js way. If there is such a thing.

Any advice or tips would be much appreciated.

Answer 1

I'm responsible for tile.stamen.js. Sorry for the headache.

The problem here is that our script needs access to the Google Maps namespace ( google.maps ) so that it can create the StamenMapType class and have it inherit methods from Google's ImageMapType . If you absolutely need to use RequireJS (which I wouldn't suggest, exactly because it makes simple stuff like this awkward), you'll need to rewrite the whole Google-specific portion of tile.stamen.js (lines 155-177) to look something like this:

exports.makeStamenMapType = function(name, gmaps) {
    if (!gmaps) gmaps = google.maps;
    var provider = getProvider(name);
    return new gmaps.ImageMapType({
        "getTileUrl": function(coord, zoom) {
            var index = (zoom + coord.x + coord.y) % SUBDOMAINS.length;
            return [
                provider.url
                    .replace("{S}", SUBDOMAINS[index])
                    .replace("{Z}", zoom)
                    .replace("{X}", coord.x)
                    .replace("{Y}", coord.y)
            ];
        },
        "tileSize": new gmaps.Size(256, 256),
        "name":     name,
        "minZoom":  provider.minZoom,
        "maxZoom":  provider.maxZoom
    });
};

Then you'd use:

var toner = makeStamenMapType("toner", gmaps);

where gmaps is your required Google Maps API object.