choropleth.js

var d3 = require('d3');
var queue = require('d3-queue').queue;
var topojson = require('topojson');

var d3 = require('d3');
// Require the library and give it a reference to d3
var Prerender = require('d3-pre');
var prerender = Prerender(d3);

prerender.start();


var width = 960,
    height = 600;

var rateById = d3.map();

var quantize = d3.scale.quantize()
    .domain([0, .15])
    .range(d3.range(9).map(function(i) { return "q" + i + "-9"; }));

var projection = d3.geo.albersUsa()
    .scale(1280)
    .translate([width / 2, height / 2]);

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

var svg = d3.select("#interactive").append("svg")
    .attr("viewBox", '0 0 ' + width + ' ' + height);
    // .attr("width", width)
    // .attr("height", height);

queue()
    .defer(d3.json, "./js/us.json")
    .defer(d3.tsv, "./js/unemployment.tsv", function(d) { rateById.set(d.id, +d.rate); })
    .await(ready);

function ready(error, us) {
  if (error) throw error;

  svg.append("g")
      .attr("class", "counties")
    .selectAll("path")
      .data(topojson.feature(us, us.objects.counties).features)
    .enter().append("path")
      .attr("class", function(d) { return quantize(rateById.get(d.id)); })
      .attr("d", path);

  svg.append("path")
      .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; }))
      .attr("class", "states")
      .attr("d", path);
}

d3.select(self.frameElement).style("height", height + "px");