JSFiddle - React, Tailwind, and code Playground

by Shawn Allen

HTML

<!DOCTYPE html>
<html>
  <head>
    <title>Force-Directed Layout</title>
    <script type="text/javascript" src="http://mbostock.github.com/d3/d3.js"></script>
  </head>
  <body>
  </body>
</html>

CSS

circle {
  stroke-width: 1.5px;
}

line {
  stroke: #999;
}

JavaScript

var w = 960,
    h = 500,
    r = 6,
    dist = 50,
    fill = d3.scale.category20();

var force = d3.layout.force()
    .charge(-120)
    .linkDistance(dist)
    .size([w, h]);

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

d3.json("http://bl.ocks.org/d/1129492/readme.json", function(json) {
    var link = svg.selectAll("line").data(json.links).enter().append("svg:line");

    var node = svg.selectAll("circle")
        .data(json.nodes)
        .enter()
        .append("svg:circle")
            .attr("r", r - .75)
            .style("fill", function(d) {
                return fill(d.group);
            })
            .style("stroke", function(d) {
                return d3.rgb(fill(d.group)).darker();
            })
            .call(force.drag)
            .on("mouseover", function(d) {
                d.fixed = true;
                d3.select(this).attr("r", r * 2);
                force.stop();
                force.linkDistance(function(link) {
                    var len = isConnected(d, link.source) || isConnected(d, link.target)
                        ? dist * 2
                        : dist * 1.25;
                    return len;
                });
                force.start();
            })
            .on("mouseout", function(d) {
                d.fixed = false;
                d3.select(this).attr("r", r - .75);
                force.stop();
                force.linkDistance(dist);
                force.start();
            });

    force.nodes(json.nodes)
        .links(json.links)
        .on("tick", tick)
        .start();

    var linkedByIndex = {};
    json.links.forEach(function(d) {
        linkedByIndex[d.source.index + "," + d.target.index] = 1;
    });

    function isConnected(a, b) {
        return linkedByIndex[a.index + "," + b.index] || linkedByIndex[b.index + "," + a.index] || a.index == b.index;
    }

    function tick() {
        node.attr("cx", function(d) {
     ...