Cascaded Treemap

Based on work by Matteo Abrate and Lü and Fogarty.

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  font: 10px sans-serif;
  margin: 3px;
  position: relative;
}

.node {
  position: absolute;
  overflow: hidden;
  padding: 3px;
  box-shadow: 0 2px 3px rgba(0,0,0,0.4);
  box-sizing: border-box;
}

.node--internal {
  font-weight: bold;
}

.node--hover {
  padding: 2px;
  border: solid 1px #000;
}

</style>
<body>
<script src="//d3js.org/d3.v4.0.0-alpha.35.min.js"></script>
<script>

var width = 960,
    height = 1060,
    offset = 3;

var format = d3.format(",d");

var color = d3.scaleMagma()
    .domain([-4, 4]);

var stratify = d3.stratify()
    .parentId(function(d) { return d.id.substring(0, d.id.lastIndexOf(".")); });

var treemap = d3.treemap()
    .size([width, height])
    .paddingInner(1)
    .paddingOuter(offset)
    .paddingTop(function(d) { return d.depth < 3 ? 19 : offset; })
    .round(true);

d3.csv("flare.csv", function(error, data) {
  if (error) throw error;

var root = stratify(data)
      .sum(function(d) { return d.value; })
      .sort(function(a, b) { return b.height - a.height || b.value - a.value; });

cascade(treemap(root));

d3.select("body")
    .selectAll(".node")
    .data(root.descendants())
    .enter().append("div")
      .attr("class", function(d) { return "node" + (d.children ? " node--internal" : " node--left"); })
      .attr("title", function(d) { return d.id + "\n" + format(d.value); })
      .style("left", function(d) { return d.x0 + "px"; })
      .style("top", function(d) { return d.y0 + "px"; })
      .style("width", function(d) { return d.x1 - d.x0 + "px"; })
      .style("height", function(d) { return d.y1 - d.y0 + "px"; })
      .style("background", function(d) { return color(d.depth); })
      .each(function(d) { d.node = this; })
      .on("mouseover", hovered(true))
      .on("mouseout", hovered(false))
      .text(function(d) { return d.id.substring(d.id.lastIndexOf(".") + 1).split(/(?=[A-Z][^A-Z])/g).join("\u200b"); });
});

function hovered(hover) {
  return function(d) {
    d3.selectAll(d.ancestors().map(function(d) { return d.node; }))
        .classed("node--hover", hover);
  };
}

</script>

https://d3js.org/d3.v4.0.0-alpha.35.min.js