D3 Examples - 29. Link Nodes by Name

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<!DOCTYPE html>
<meta charset="utf-8">
<style>
​
.node {
  stroke: #000;
  stroke-width: 1.5px;
}
​
.link {
  stroke: #999;
  stroke-width: 1.5px;
}
​
</style>
<svg width="960" height="500"></svg>
​
<script src="//d3js.org/d3.v4.min.js"></script>
​
<script>
​
var svg = d3.select("svg"),
    width = +svg.attr("width"),
    height = +svg.attr("height");
​
var simulation = d3.forceSimulation()
// ---- trial and error on .strength(value)
    .force("charge", d3.forceManyBody().strength(-300))
// ---- trial and error on .distance(value)
    .force("link", d3.forceLink().id(function(d) { return d.id; }).distance(90))
// ---central position
    .force("x", d3.forceX(width / 4))
    .force("y", d3.forceY(height / 2))
//     .on("tick", ticked);
​
// ---- create empty nodeList
var link = svg.selectAll(".link"),
    node = svg.selectAll(".node");
​
  
  
d3.json("graph.json", function(error, graph) {
  if (error) throw error;
​
  
  
//   load graph.nodes and graph.links to simulation
  simulation.nodes(graph.nodes);
  simulation.force("link").links(graph.links);
//   as a result, node and link's data contain x,y,vx,vy now 
​
  
  
//---- replace empty NodeList with lines and circles   
  link = link
    .data(graph.links)
    .enter().append("line")
      .attr("class", "link");
​
  node = node
    .data(graph.nodes)
    .enter().append("circle")
      .attr("class", "node")
      .attr("r", 6)
      .style("fill", function(d) { return d.id; });
​
// --- reveal node and link
  simulation
      .on("tick", ticked);
​
});
​
  
  
  
function ticked() {
  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; });
}
​
</script>
​
    