How to create d3.js Collapsible force layout with non tree data?

Question

I have a d3 force directed layout with data in a similar structure below. Is it possible to apply collapsible force layout such as http://bl.ocks.org/mbostock/1062288 to it?

Answer 1

Try this:

    var width = 960,height = 500;

    var force = d3.layout.force().size([width, height]).charge(-400)
                .linkDistance(40)
                .on("tick", tick);

         var drag = force.drag().on("dragstart", dragstart);

           var svg = d3.select("body").append("svg").attr("width", width)
                        .attr("height", height);

           var link = svg.selectAll(".link"),
                  node = svg.selectAll(".node");

            d3.json("graph.json", function(error, graph) {
                     force.nodes(graph.nodes).links(graph.links)
                         .start();

        link = link.data(graph.links).enter().append("line")
                      .attr("class", "link");

                  node = node.data(graph.nodes)
                 .enter().append("circle")
                 .attr("class", "node")
                 .attr("r", 12)
                 .call(drag);
         });

         function tick() {
              link.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; });

             node.attr("cx", function(d) { return d.x; })
                  .attr("cy", function(d) { return d.y; });
           }



           function dragstart(d) {
                  d3.select(this).classed("fixed", d.fixed = true);
              }

You should use json file like this:

graph.json

      {
        "nodes": [
         {"x": 469, "y": 410},
         {"x": 493, "y": 364},
         {"x": 442, "y": 365},
         {"x": 467, "y": 314},
     ],
         "links": [
          {"source":  0, "target":  1},
          {"source":  1, "target":  2},
          {"source":  2, "target":  0},
          {"source":  1, "target":  3},
          {"source":  3, "target":  2},
      ]
     }