digram.js

<script src="d3.v4.min.js"></script>
<svg width="960" height="900"></svg>

<script>
    d3.csv("categories.csv", function(error, data) {
        if (error) throw error;

        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height"),
            g = svg.append("g").attr("transform", "translate(40,0)");

        var i = 0,
            duration = 750,
            root;

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

        data.forEach(function(d) {
            if (d.parentId == "null") { d.parentId = null}
            if (d.parentName == "null") { d.parentName = null}
        });

        // Assigns parent, children, height, depth
        root = d3.stratify()
            .id(function(d) { return d.id; })
            .parentId(function(d) { return d.parentId; })
            (data);
        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
            }
        }

        function update(source) {

            // 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 * 180});

            // ****************** 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);

            // 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.y + "," + d.x + ")";
                });

            // 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.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
            }

            // Toggle children on click.
            function click(d) {
                if (d.children) {
                    d._children = d.children;
                    d.children = null;
                } else {
                    d.children = d._children;
                    d._children = null;
                }
                update(d);
            }
        }
    });

</script>