How to make labels and nodes in D3 forced layout clickable to navigate to a URL?

Question

I am using a force based layout using D3 and was wondering if it's possible that when I click either the nodes or the labels, I am automatically taken to the url stored in that node/label? If it is, how can I achieve this?

This is how the graph will actually look (labels indicate the URL itself)

I am sharing the javascript code I am using to generate the D3 graph. In the code, I am currently using dummy data which will actually be replaced by URLs.

document.addEventListener('DOMContentLoaded', function () {
    drawVisual();
});

function drawVisual()
{
    //document.getElementById('myMSG').innerHTML = "last name"+localStorage.lastname;
    /*var getArr = [];
    getArr = JSON.parse(localStorage.getItem('storeArray'));
    document.getElementById('myMSG').innerHTML = getArr[1].parentURL;*/


    //var w = 1024, h = 768;

    var w=window.innerWidth
    || document.documentElement.clientWidth
    || document.body.clientWidth;

    var h=window.innerHeight
    || document.documentElement.clientHeight
    || document.body.clientHeight;
    //var w = 1024, h = 768;

    //var vis = d3.select("#tab_5_contents").append("svg:svg").attr("width", w).attr("height", h);
    var vis = d3.select("#forcedLayoutGraph").append("svg:svg").attr("width", w).attr("height", h);

            var QueuedORG = [];
            //QueuedORG = JSON.parse(localStorage.getItem('storeArray'));
            QueuedORG.push({url: "Root", parentURL: "Root", used:0});
            QueuedORG.push({url: "a", parentURL: "Root", used:0});
            QueuedORG.push({url: "b", parentURL: "Root", used:0});
            QueuedORG.push({url: "c", parentURL: "Root", used:0});
            QueuedORG.push({url: "d", parentURL: "Root", used:0});
            QueuedORG.push({url: "e", parentURL: "a", used:0});
            QueuedORG.push({url: "f", parentURL: "a", used:0});
            QueuedORG.push({url: "g", parentURL: "a", used:0});
            QueuedORG.push({url: "h", parentURL: "a", used:0});
            QueuedORG.push({url: "p", parentURL: "b", used:0});
            QueuedORG.push({url: "q", parentURL: "b", used:0});
            QueuedORG.push({url: "r", parentURL: "b", used:0});
            QueuedORG.push({url: "x", parentURL: "c", used:0});
            QueuedORG.push({url: "y", parentURL: "x", used:0});
            QueuedORG.push({url: "y", parentURL: "c", used:0});
            QueuedORG.push({url: "x", parentURL: "a"});
            QueuedORG.push({url: "y", parentURL: "b"});


            var nodes = [];

            var labelAnchors = [];
            var labelAnchorLinks = [];
            var links = [];

            for(var i = 0; i < QueuedORG.length; i++) 
            {
                var nodeExists = 0;

                //check to see if a node for the current url has already been created. If yes, do not create a new node
                for(var j = 0; j < nodes.length; j++)  
                {
                    if(QueuedORG[i].url == nodes[j].label)
                        nodeExists = 1;

                }

                if (nodeExists == 0)
                {
                    var urlLabel = QueuedORG[i].url;
                    //remove 'http://' part
                    /*urlLabel = urlLabel.split("http://")[1];
                    if(urlLabel.match("www"))
                    urlLabel = urlLabel.split("www.")[1];
                    var rest = urlLabel.split("\.")[1];
                    urlLabel = urlLabel.split("\.")[0];*/

                    var node = {
                        label : QueuedORG[i].url,
                        category : QueuedORG[i].category
                    };
                    nodes.push(node);
                    labelAnchors.push({
                        node : node
                    });
                    labelAnchors.push({
                        node : node
                    });
                }
            };

            for(var i=0;i<nodes.length; i++)
            {
                console.log("node i:"+i+nodes[i]+"\n");
                console.log("labelAnchor i:"+i+labelAnchors[i]+"\n");
            }

            //To create links for connecting nodes
            for(var i = 0; i < QueuedORG.length; i++) 
            {
                var srcIndx = 0, tgtIndx = 0;
                for(var j = 0; j < nodes.length; j++)
                {
                    if( QueuedORG[i].url == nodes[j].label ) //to find the node number for the current url
                    {
                        srcIndx = j;
                    }

                    if( QueuedORG[i].parentURL == nodes[j].label ) //to find the node number for the parent url
                    {
                        tgtIndx = j;
                    }
                }
                //console.log("src:"+srcIndx+" tgt:"+tgtIndx);

                //connecting the current url's node to the parent url's node
                links.push({
                    source : srcIndx,
                    target : tgtIndx,
                    weight : 1,
                });

                labelAnchorLinks.push({
                    source : srcIndx * 2,
                    target : srcIndx * 2 + 1,
                    weight : 1
                });
            };

            var force = d3.layout.force().size([w, h]).nodes(nodes).links(links).gravity(1).charge(-10000).linkStrength(function(x) {
                return x.weight * 10                                            // charge is for inter-node repel, link distance is node-node distance 
            });
            force.linkDistance(function(d) {
                return d.weight * 100;
            });

            force.start();

            var force2 = d3.layout.force().nodes(labelAnchors).links(labelAnchorLinks).gravity(0).linkStrength(10).charge(-500).size([w, h]);   //charge is for inter-label repel, link distance is node-label distance
            force2.linkDistance(function(d) {
                return d.weight * 10;
            });

            force2.start();

            var link = vis.selectAll("line.link").data(links).enter().append("svg:line").attr("class", "link").style("stroke", "#CCC");

            var colors = {"1": "black", "2": "blue", "3": "red"};           // 1=root node 2=blog nodes 3=.org nodes
            var shape = {"1": "diamond", "2": "cross", "3": "circle"};

            var node = vis.selectAll("g.node").data(force.nodes()).enter().append("path").attr("class", "node").call(force.drag);
        //node.append("circle").attr("r", 5).style("stroke", "#FFF").style("stroke-width", 3).attr("class", function(d) {return "node category"+d.category});

            node.attr("d", d3.svg.symbol().type(function(d) {return shape[d.category];})).style("stroke", "#FFF").style("fill", function(d){ return colors[d.category];});

            var anchorLink = vis.selectAll("line.anchorLink").data(labelAnchorLinks)//.enter().append("svg:line").attr("class", "anchorLink").style("stroke", "#999");

            var anchorNode = vis.selectAll("g.anchorNode").data(force2.nodes()).enter().append("svg:g").attr("class", "anchorNode");
            anchorNode.append("svg:circle").attr("r", 0).style("fill", "#FFF");
            anchorNode.append("svg:text").text(function(d, i) {
                return i % 2 == 0 ? "" : d.node.label
            }).style("fill", "#555").style("font-family", "Arial").style("font-size", 12);

            var updateLink = function() {
                this.attr("x1", function(d) {
                    return d.source.x;
                }).attr("y1", function(d) {
                    return d.source.y;
                }).attr("x2", function(d) {
                    return d.target.x;
                }).attr("y2", function(d) {
                    return d.target.y;
                });
            }

            var updateNode = function() {
                this.attr("transform", function(d) {
                    return "translate(" + d.x + "," + d.y + ")";
                });

            }

            force.on("tick", function() {

                force2.start();

                node.call(updateNode);

                anchorNode.each(function(d, i) {
                    if(i % 2 == 0) {
                        d.x = d.node.x;
                        d.y = d.node.y;
                    } else {
                        var b = this.childNodes[1].getBBox();

                        var diffX = d.x - d.node.x;
                        var diffY = d.y - d.node.y;

                        var dist = Math.sqrt(diffX * diffX + diffY * diffY);

                        var shiftX = b.width * (diffX - dist) / (dist * 2);
                        shiftX = Math.max(-b.width, Math.min(0, shiftX));
                        var shiftY = 5;
                        this.childNodes[1].setAttribute("transform", "translate(" + shiftX + "," + shiftY + ")");
                    }
                });

                anchorNode.call(updateNode);

        link.call(updateLink);
        anchorLink.call(updateLink);

    });
}

Answer 1

Generally speaking, you can add click events to SVG elements in D3.js using

.on('click', function(d, i) {
  window.location.href = d.url;
})

d is the data object and the i is in the index of d within the collection.

Just add that click handler to your text node as well as your node (path) node like in this fiddle http://jsfiddle.net/jNyrf/

Answer 2

You have two options here.

• You can use the .on("click", ...) handler to set the current page to the target.
• You can use an a element with .attr("xlink:href", url) that contains the element acting as a hyperlink to set the link in a more traditional way.

More information in this question/answer, although I believe you don't have to import the xlink namespace explicitly, at least not in the latest version of D3.