script.js

// Set the dimensions and margins of the diagram
var margin = { top: 25, right: 110, bottom: 25, left: 110 },
    width = 100% - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom,
    linkLength = 180;

// Responsive width
d3.select("body")
    .attr("onresize","updateWidth()")
    .attr("onload", "updateWidth()");

function updateWidth () {
    width = window.innerWidth-margin.left-margin.right-25;
    linkLength=(width-50)/4; 
    update(root);
}

// 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.right + margin.left)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate("
        + margin.left + "," + margin.top + ")");
        
var i = 0, duration = 750, root;

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

// Assigns parent, children, height, depth
root = d3.hierarchy(treeData, function(d) { return d.children; });
root.x0 = height / 2;
root.y0 = 0;

// Collapse after the second level
root.children.forEach(collapse);

update(root);

// Collapse the node and all it's children
function collapse(d) {
    if (d.children) {
        d._children = d.children
        d._children.forEach(collapse)
        d.children = null
    }
}

/* MODAL STUFF */
// Get the modal element
var modal = document.getElementById("myModal");
// Get the <span> element that closes the modal
var span = document.getElementsByClassName("close")[0];
// When the user clicks on <span> (x), close the modal
span.onclick = function() {
  modal.style.display = "none";
}
// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
  if (event.target == modal) {
    modal.style.display = "none";
  }
}

function update(source) {

    //compute the new height of the tree and svg
    var levelWidth = [1];
    var childCount = function(level, n) {
        
        if(n.children && n.children.length > 0) {
        if(levelWidth.length <= level + 1) levelWidth.push(0);
        
        levelWidth[level+1] += n.children.length;
        n.children.forEach(function(d) {
            childCount(level + 1, d);
        });
        }
    };
    childCount(0, root);  
    
    var calcHeight = Math.max(d3.max(levelWidth)*35, window.screen.height*0.77 -margin.top - margin.bottom);
    height = calcHeight; // 25 pixels per line  
    
    // Update tree and svg dimensions
    treemap = treemap.size([height, width]);    
    d3.select("svg")
        .attr("height",height + margin.top + margin.bottom)
        .attr("width",width + margin.left + margin.right);
    
    // Assigns the x and y position for the nodes
    var treeData = treemap(root);

    // Compute the new tree layout.
    var nodes = treeData.descendants(),
        links = treeData.descendants().slice(1);

    // Normalize for fixed-depth.
    nodes.forEach(function(d) { d.y = d.depth * linkLength });

    // ****************** Nodes section ***************************

    // Update the nodes...
    var node = svg.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.y0 + "," + source.x0 + ")";
        })
        .on('click', click);

    // Circle color states
    var nodeColorExpanded = "#faa323",
        nodeColorCollapsed = "#ffca61";
    
    // Add Circle for the nodes
    nodeEnter.append('circle')
        .attr('class', 'node')
        .attr('r', 1e-6)
        .style("fill", function(d) {
            return d._children ? nodeColorCollapsed : nodeColorExpanded;
        });

    // 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";
        })
        .style("color", "#CCCCCC")
        .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.y + "," + d.x + ")";
        });

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


    // Remove any exiting nodes
    var nodeExit = node.exit().transition()
        .duration(duration)
        .attr("transform", function(d) {
            return "translate(" + source.y + "," + source.x + ")";
        })
        .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 = svg.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 = { x: source.x0, y: source.y0 }
            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) {
        d.x0 = d.x;
        d.y0 = d.y;
    });

    // Creates a curved (diagonal) path from parent to the child nodes
    function diagonal(s, d) {

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

        return path
    }

    // Expand node children
    function nodeExpand(d) {
        if(d._children){
            d.children = d._children;
            d._children = null;
            console.log("expanding");
        }
    }

    // Recursively collapse all node descendants
    function nodeCollapseDescendants(d) {
        if (d.children) {
            d.children.forEach(nodeCollapseDescendants);
            d._children = d.children;
            d.children = null;
            console.log("collapsing");
        }
    }
    
    // Toggle children on click.
    function click(d) {
        console.log(d);
        if(d._children)
            nodeExpand(d);
        else if(d.children)
            nodeCollapseDescendants(d);
        else if (d.data.description) {
            // Open modal
            modal.style.display = "block";
            document.getElementById("modalTitle").innerHTML = d.data.name + ": " + d.data.title + " (" + d.data.credits + ")";
            document.getElementById("modalBody").innerHTML = d.data.description;
        } 
        
        update(d);
    }
}