D3 Examples - vertical tree

Burrow - recursive nesting

An updated version of the burrow function from d3 src tree in plain JavaScript. This function takes an array of keys to generate a hierarchy.

Compared to d3.nest: burrow allows for branches of arbitrary depth.

Compared to d3.stratify: parent nodes do not need to be specified as separate rows in the tabular data. Parents are created automatically as they are encountered.

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<!DOCTYPE html>
<meta charset="utf-8">
<style>
​
.node rect {
  fill: #fafafa;
  stroke: #ddd;
  width: 30px;
  height: 2em;
  x: -15px;
  y: -1em;
}
​
.node text {
  font: 10px sans-serif;
}
​
.node--internal circle {
  fill: #555;
}
​
.node text {
  text-shadow: 0 1px 0 #fff, 0 -1px 0 #fff, 1px 0 0 #fff, -1px 0 0 #fff;
}
​
.link {
  fill: none;
  stroke: #555;
  stroke-opacity: 0.2;
/*   stroke-width: 1.5px; */
}
​
</style>
<body>
<script src="//d3js.org/d3.v4.0.0-alpha.29.js"></script>
<script>
​
var width = 960,
    height = 500,
    radius = 250,
        curve = 0.5;
​
var burrow = function(table) {
  // create nested object
  var obj = {};
  table.forEach(function(row) {
    // start at root
    var layer = obj;
    // create children as nested objects
    row.taxonomy.forEach(function(key) {
      layer[key] = key in layer ? layer[key] : {};
      layer = layer[key];
    });    
  });
  console.log(obj); 
  // recursively create children array
  var descend = function(obj, depth) {
    var arr = [];
    var depth = depth || 0;
    for (var k in obj) {
      var child = {
        name: k,
        depth: depth,
        children: descend(obj[k], depth+1),
      };
      arr.push(child);
    }
    return arr;
  };
​
  
  // use descend to create nested children arrys
  return {
    name: "root",
    children: descend(obj, 1),
    depth: 0
  }
};
    
var tree = d3.tree()
    .size([width-40,height-40])
    .separation(function(a, b) { return (a.parent == b.parent ? 1 : 2)/2; });
​
var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height)
  .append("g")
    .attr("transform", "translate(" + 20 + "," + 20 + ")");
​
d3.tsv("d3-hierarchy.tsv", function(error, data) {
  if (error) throw error;
​
  // splitting keys into an array is required before passing data into burrow
  data.forEach(function(row) {
    row.taxonomy = row.file.split("/");
  });
 
​
  var root = d3.hierarchy(burrow(data));
  console.log(root);
  tree(root);
​
  var link = svg.selectAll(".link")
      .data(root.descendants().slice(1))
    .enter().append("path")
      .attr("class", "link")
        .attr("stroke-width", function(d){return d.value})
      .attr("d", function(d) {
        return "M" + [d.x, d.y]
            + "C" + [d.x, (d.y + d.parent.y) * curve]
            + " " + [d.parent.x, (d.y + d.parent.y) * (1-curve)]
            + " " + [d.parent.x, d.parent.y];
      });
​
  var node = svg.selectAll(".node")
      .data(root.descendants())
    .enter().append("g")
      .attr("class", function(d) { return "node" + (d.children ? " node--internal" : " node--leaf"); })
      .attr("transform", function(d) { return "translate(" + d.x + "," + (d.y) + ")" });
​
  node.append("rect");
​
  node.append("text")
      .text(function(d) { return d.data.name + d.data; });
});
​
</script>
​
    