TopoJSON-aware Leaflet layer

L.TopoJSON.js

/*
You'll need something like this in your HTML:
<script src="http://d3js.org/topojson.v1.min.js"></script>
*/

L.TopoJSON = L.GeoJSON.extend({
  addData: function(jsonData) {    
    if (jsonData.type === "Topology") {
      for (key in jsonData.objects) {
        geojson = topojson.feature(jsonData, jsonData.objects[key]);
        L.GeoJSON.prototype.addData.call(this, geojson);
      }
    }    
    else {
      L.GeoJSON.prototype.addData.call(this, jsonData);
    }
  }  
});

/* 
The MIT License (MIT)

Copyright (c) 2013 Ryan Clark

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

Nice! I just tested something similar myself a moment ago. I like the simplicity of your implementation. Is there any particular license you're releasing this under?

Wow -- you were on this before I even knew if it worked. Well it does! And now there's more license than code -- hurray!

Any ideas how to make this work in combination with leaflet-ajax?

Thanks for this! You could add

return this;

to allow the same method chaining used in L.GeoJSON for full compatibility.

Additional info with similar approach: http://blog.webkid.io/maps-with-leaflet-and-topojson/

Forked and edited to be used the same as L.geoJson()

https://gist.github.com/brendanvinson/0e3c3c86d96863f1c33f55454705bca7