In-browser GIS buffer

In-browser GIS buffer via turf.js

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <style>
      .county {
        fill: rgb(97, 183, 58);
        stroke: #fff;
        stroke-width: 2px;
      }

.county.buffered {
        fill: rgba(255, 255, 255, 0.3);
        stroke: none;
      }
    </style>
  </head>
  <body>
    <script src="//api.tiles.mapbox.com/mapbox.js/plugins/turf/v2.0.0/turf.min.js"></script>
    <script src="//d3js.org/d3.v3.min.js" charset="utf-8"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/topojson/1.6.20/topojson.min.js"></script>
    <script>
      var width = 960,
          height = 500;

var projection = d3.geo.conicConformal()
        .rotate([90, 0])
        .center([0.1995, 44.75])
        .parallels([29.5, 45.5])
        .scale(6000)
        .translate([width/2, height/2])
        .precision(0.1);

var path = d3.geo.path()
          .projection(projection);

var svg = d3.select("body").append("svg")
        .attr("width", width)
        .attr("height", height);

d3.json("wi.json", function(error, wi) {
        if (error) throw error;

wi = topojson.feature(wi, wi.objects.wi);
        var wiBuffered = buffer(wi, -5, "miles");

svg.selectAll(".county").data(wi.features)
          .enter().append("path")
            .attr("class", "county")
            .attr("d", path);

svg.selectAll(".county.buffered").data(wiBuffered.features)
          .enter().append("path")
            .attr("class", "county buffered")
            .attr("d", path);
      });

return {
          type: "FeatureCollection",
          features: features,
          properties: null
        };
      }
    </script>
  </body>
</html>

https://api.tiles.mapbox.com/mapbox.js/plugins/turf/v2.0.0/turf.min.js

https://d3js.org/d3.v3.min.js

https://cdnjs.cloudflare.com/ajax/libs/topojson/1.6.20/topojson.min.js