Vertical Tree diagram with v4 and collapsing and expanding

readme.md

A little thing to try to show how to make a top down collapsable tree map with d3 v4. It's not a great example and has a number of extraneous functions as I was messing around just trying to learn how to use this layout a little bit.

Mostly copied from: https://bl.ocks.org/d3noob/43a860bc0024792f8803bba8ca0d5ecd

But hopefully I'm going to hack it so show how to max and or min heapify an array of numerical data. But transitions in d3 are hard...

But for a great and maybe more useful viz that works and has a decent explanation of how to use a heap data structure check out http://www.benfrederickson.com/heap-visualization/

heaper.js

var numbs = [ 4, 7, 8, 2, 3, 1, 23 ]

var margin = {top: 20, right: 90, bottom: 30, left: 90},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var i = 0,
    duration = 750,
    root;

var counter = 0;
var treeData = {};

var svg = d3.select("#heap")
        .append("svg")
        .attr("width", width + margin.right + margin.left)
        .attr("height", height + margin.top + margin.bottom)

var g = svg.append("g")
        .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var tree = d3.tree()
            .size([width, height]);


function buildHeap(inData){

   var newsource = {name: inData[0], children: getChildren(0, inData) }
//   console.log('dl', newsource)

   root = d3.hierarchy(newsource, function(d) { return d.children; });

   root.x0 = 0;
   root.y0 = width/2;

   update(root)
}


// just leaving this global so i can mess with it in the console
var nodes;

function update(source){
//  root = d3.hierarchy(newsource, function(d) { return d.children; });

  var treeData = tree(root)
  nodes = treeData.descendants();
  var links = treeData.descendants().slice(1);

  // ****************** Nodes section ***************************
  // Update the nodes...
  var node = g.selectAll('g.node')
        .data(nodes, function(d) {return d.id || (d.id = ++i); });

           // Enter any new modes at the parent's previous position.
  var nodeEnter = node.enter().append('g')
            .attr('class', 'node')
            .attr("transform", function(d) {
                 return "translate(" + source.x0 + "," + source.y0 + ")";
             })
            .on('click', click);

  // Add Circle for the nodes
  nodeEnter.append('circle')
           .attr('class', 'node')
           .attr('r', 1e-6)
           .style("fill", function(d) {
                 return d._children ? "lightsteelblue" : "#fff";
           });

// Add labels for the nodes
  nodeEnter.append('text')
          .attr("dy", ".35em")
          .attr("x", function(d) {
                return d.children || d._children ? -13 : 13;
          })
          .attr("text-anchor", function(d) {
                return d.children || d._children ? "end" : "start";
          })
           .text(function(d) { return d.data.name; });

  // UPDATE
  var nodeUpdate = nodeEnter.merge(node);

  // Transition to the proper position for the node
  nodeUpdate.transition()
        .duration(duration)
        .attr("transform", function(d) {
              return "translate(" + d.x + "," + d.y + ")";
        });

  // Update the node attributes and style
  nodeUpdate.select('circle.node')
        .attr('r', 10)
        .style("fill", function(d) {
            return d._children ? "lightsteelblue" : "#fff";
        })
        .attr('cursor', 'pointer');


  // Remove any exiting nodes
  var nodeExit = node.exit().transition()
          .duration(duration)
          .attr("transform", function(d) {
                   return "translate(" + source.x + "," + source.y + ")";
               })
          .remove();

           // On exit reduce the node circles size to 0
  nodeExit.select('circle')
          .attr('r', 1e-6);

           // On exit reduce the opacity of text labels
  nodeExit.select('text')
          .style('fill-opacity', 1e-6);

// ****************** links section ***************************

 // Update the links...
 var link = g.selectAll('path.link')
     .data(links, function(d) { return d.id; });

 // Enter any new links at the parent's previous position.
 var linkEnter = link.enter().insert('path', "g")
     .attr("class", "link")
     .attr('d', function(d){
       var o = {y: source.y0, x: source.x0}
       return diagonal(o, o)

     });

 // UPDATE
 var linkUpdate = linkEnter.merge(link);

 // Transition back to the parent element position
 linkUpdate.transition()
     .duration(duration)
     .attr('d', function(d){ return diagonal(d, d.parent) });

 // Remove any exiting links
 var linkExit = link.exit().transition()
     .duration(duration)
     .attr('d', function(d) {
       var o = {x: source.x, y: source.y}
       return diagonal(o, o)
     })
     .remove();

 // Store the old positions for transition.
 nodes.forEach(function(d, i){
//   console.log(d)
   d.x0 = d.x;
   d.y0 = d.y;
 });

 console.log(nodes[0])
 //nodes[0].data.children = nodes[0].data._children;
 //nodes[0].data._children = null;


}

// Takes an index and an array and finds all the children.
// returns an array which can be added to children of the root node to
// make a json thing which can be used to make a d3.hierarchy();
function getChildren(i, arr) {
        var childs = [];

        if( arr[i+1+ i] ){
          childs[0] = {name: arr[i*2+1], children: []}
          if( arr[i+i+2] ){
          //  console.log(arr[i+1+ i], arr[i+i+2])
            childs[1] = {name: arr[i * 2 + 2], children:[]}  ;
        }
        }

        var nextin = i * 2 + 1;
        if(arr[nextin*2+1]){
          //  console.log('more children')
            childs[0].children = getChildren(nextin, arr)
            childs[0]._children = null;

            if( arr[nextin*2 + 2 ]){
                childs[1].children = getChildren(nextin+1, arr);
                childs[1]._children = null;
            }
        }
        return childs;
    }


// not called but kind of what I might use to annimate the swap thing while
// balancing binary heaps
function expandChildren(index, chi){
setTimeout(function () {
 //buildHeap([ 4, 3, 2, 9, 14, 29] );
 console.log('hooho', nodes)
 if(nodes[index].children === null){
   nodes[0].children = [nodes[0]._children[chi]]
 }
 else{
   console.log( typeof nodes[0]. children)
   nodes[index].children.push(nodes[index]._children[1])
 }
// .h(nodes[0]._children[0]);
 //nodes[0]._children ;

// console.log(nodes[index])
 update(nodes[index])
 if(chi < 1){
   expandChildren(0, 1)
 }
}, 3000);

}

//expandChildren(0, 0);


// Creates a curved (diagonal) path from parent to the child nodes
// switched around all the x's and y's from orig so it's verticle
function diagonal(s, d) {
  //console.log('in diag and s = ', s);
  //console.log('d = ', d)

  path = `M ${s.x} ${s.y}
          C ${(s.x + d.x) / 2} ${s.y},
            ${(s.x + d.x) / 2} ${d.y},
            ${d.x} ${d.y}`

  return path;

}


// Toggle children on click.
function click(d) {
// use the following to superficially change the text of the node.
//  this.getElementsByTagName('text')[0].textContent = "clicked all over"

  if (d.children) {
      d._children = d.children;
      d.children = null;
    } else {
      d.children = d._children;
      d._children = null;
    }

  update(d);
}

// will make all the children null and store the real vals in _children
function collapse(d) {
  if(d.children) {
    d._children = d.children
    d.children = null;
    d._children.forEach(collapse)

  }
}


buildHeap( numbs )

index.html

<!DOCTYPE html>
<html>
    <head>
        <link rel="stylesheet" href="./style.css" />
    <script src="https://d3js.org/d3.v4.js"></script>


  </head>
  <body>
    <div id="heap">

        </div>
  <script src="heaper.js"></script>
  </body>
</html>

style.css

.node {
  cursor: pointer;
}

.node circle {
  fill: #fff;
  stroke: steelblue;
  stroke-width: 1.5px;
}

.node text {
  font: 10px sans-serif;
}

.link {
  fill: none;
  stroke: #ccc;
  stroke-width: 1.5px;
}