utilizes Mike Bostock's excellent instructions to use D3 to render GeoJSON features on a Leaflet Map
logic is wrapped into an object that extends Leaflet's own GeoJSON layer, so its easy to add to a map using Leaflet's usual pattern:
var d3Layer = new L.GeoJSON.d3({...insert geojson here...});
var map = new L.Map("map").addLayer(d3Layer);
L.GeoJSON.d3.async allows you to create a layer that references a geojson data service, such as a WFS provided by Geoserver.
var asyncD3Layer = new L.GeoJSON.d3.async("http:/url/for/geoserver/wfs");
var map = new L.Map("map").addLayer(asyncD3Layer)
check out /dist/index.html