block by d3noob 3baa7023d4d1661536a491b51460cfe9

Tree diagram using flat data with v5

Full Screen

This is a tree diagram that used data from a ‘flat’ format. It has been written with d3.js v5 and is based on the simple horizontal version here

This is designed to be used as part of documenting an update to the book D3 Tips and Tricks to version 5 of d3.js.

index.html

<!DOCTYPE html>
<meta charset="utf-8">
<style> /* set the CSS */
    
.node circle {
  fill: #fff;
  stroke: steelblue;
  stroke-width: 3px;
}

.node text { font: 12px sans-serif; }

.node--internal text {
  text-shadow: 0 1px 0 #fff, 0 -1px 0 #fff, 1px 0 0 #fff, -1px 0 0 #fff;
}

.link {
  fill: none;
  stroke: #ccc;
  stroke-width: 2px;
}

</style>

<body>

<!-- load the d3.js library -->    	
<script src="https://d3js.org/d3.v5.min.js"></script>
<script>
	
// the flat data
var flatData = [
  {"name": "Top Level", "parent": null}, 
  {"name": "Level 2: A", "parent": "Top Level" },
  {"name": "Level 2: B", "parent": "Top Level" },
  {"name": "Son of A", "parent": "Level 2: A" },
  {"name": "Daughter of A", "parent": "Level 2: A" }
];

// convert the flat data into a hierarchy 
var treeData = d3.stratify()
  .id(function(d) { return d.name; })
  .parentId(function(d) { return d.parent; })
  (flatData);

// assign the name to each node
treeData.each(function(d) {
    d.name = d.id;
  });

// set the dimensions and margins of the diagram
var margin = {top: 20, right: 90, bottom: 30, left: 90},
    width = 660 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

// declares a tree layout and assigns the size
var treemap = d3.tree()
    .size([height, width]);

//  assigns the data to a hierarchy using parent-child relationships
var nodes = d3.hierarchy(treeData, function(d) {
    return d.children;
  });

// maps the node data to the tree layout
nodes = treemap(nodes);

// append the svg object to the body of the page
// appends a 'group' element to 'svg'
// moves the 'group' element to the top left margin
var svg = d3.select("body").append("svg")
      .attr("width", width + margin.left + margin.right)
      .attr("height", height + margin.top + margin.bottom),
    g = svg.append("g")
      .attr("transform",
            "translate(" + margin.left + "," + margin.top + ")");

// adds the links between the nodes
var link = g.selectAll(".link")
    .data( nodes.descendants().slice(1))
  .enter().append("path")
    .attr("class", "link")
    .attr("d", function(d) {
       return "M" + d.y + "," + d.x
         + "C" + (d.y + d.parent.y) / 2 + "," + d.x
         + " " + (d.y + d.parent.y) / 2 + "," + d.parent.x
         + " " + d.parent.y + "," + d.parent.x;
       });

// adds each node as a group
var node = g.selectAll(".node")
    .data(nodes.descendants())
  .enter().append("g")
    .attr("class", function(d) { 
      return "node" + 
        (d.children ? " node--internal" : " node--leaf"); })
    .attr("transform", function(d) { 
      return "translate(" + d.y + "," + d.x + ")"; });

// adds the circle to the node
node.append("circle")
  .attr("r", 10);

// adds the text to the node
node.append("text")
  .attr("dy", ".35em")
  .attr("x", function(d) { return d.children ? -13 : 13; })
  .style("text-anchor", function(d) { 
    return d.children ? "end" : "start"; })
  .text(function(d) { return d.data.name; });
    
</script>
</body>