title: d3.js Sankey using named nodes
body: <p>I've created my first sankey diagram with the d3.js framework.</p>
  
  <p>My nodes and links have the following structure:</p>
  
  <pre><code>"nodes": [{
       "name" : "TestViewCode",
       "id" : "environment_score"
  }],
  
  "links" : [
    {
       "source" : 9,
       "value" : 0.00283706180951111,
       "target" : 0
    }]
  </code></pre>
  
  <p>And the following javascript code:</p>
  
  <pre><code>&lt;script&gt;
    var colors = {
          'environment':         '#edbd00',
          'social':              '#367d85',
          'animals':             '#97ba4c',
          'health':              '#f5662b',
          'research_ingredient': '#3f3e47',
          'fallback':            '#9f9fa3'
        };
  
  
    d3.json("file:///Users/.../Desktop/jsonpg.json", function(error, json) {
      var chart = d3.select("#chart").append("svg").chart("Sankey.Path");
  
  
      chart
        .name(label)
        .colorNodes(function(name, node) {
          return color(node, 1) || colors.fallback;
        })
  
  
        .colorLinks(function(link) {
          return color(link.source, 4) || color(link.target, 1) || colors.fallback;
        })
        .nodeWidth(15)
        .nodePadding(10)
        .spread(true)
        .iterations(0)
        .draw(json);
  
      function label(node) {
        return node.name.replace(/\s*\(.*?\)$/, '');
      }
  
      function color(node, depth) {
        var id = node.id.replace(/(_score)?(_\d+)?$/, '');
  
        if (colors[id]) {
          return colors[id];
        } else if (depth &gt; 0 &amp;&amp; node.targetLinks &amp;&amp; node.targetLinks.length == 1) {
          return color(node.targetLinks[0].source, depth-1);
        } else {
          return null;
        }
      }
  
    });
  
  &lt;/script&gt;
  </code></pre>
  
  <p>sankey.js</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>d3.sankey = function() {
    var sankey = {},
        nodeWidth = 24,
        nodePadding = 8,
        size = [1, 1],
        nodes = [],
        links = [];
  
    sankey.nodeWidth = function(_) {
      if (!arguments.length) return nodeWidth;
      nodeWidth = +_;
      return sankey;
    };
  
    sankey.nodePadding = function(_) {
      if (!arguments.length) return nodePadding;
      nodePadding = +_;
      return sankey;
    };
  
    sankey.nodes = function(_) {
      if (!arguments.length) return nodes;
      nodes = _;
      return sankey;
    };
  
    sankey.links = function(_) {
      if (!arguments.length) return links;
      links = _;
      return sankey;
    };
  
    sankey.size = function(_) {
      if (!arguments.length) return size;
      size = _;
      return sankey;
    };
  
    sankey.layout = function(iterations) {
      computeNodeLinks();
      computeNodeValues();
      computeNodeBreadths();
      computeNodeDepths(iterations);
      computeLinkDepths();
      return sankey;
    };
  
    sankey.relayout = function() {
      computeLinkDepths();
      return sankey;
    };
  
    sankey.link = function() {
      var curvature = .5;
  
      function link(d) {
        var x0 = d.source.x + d.source.dx,
            x1 = d.target.x,
            xi = d3.interpolateNumber(x0, x1),
            x2 = xi(curvature),
            x3 = xi(1 - curvature),
            y0 = d.source.y + d.sy + d.dy / 2,
            y1 = d.target.y + d.ty + d.dy / 2;
        return "M" + x0 + "," + y0
             + "C" + x2 + "," + y0
             + " " + x3 + "," + y1
             + " " + x1 + "," + y1;
      }
  
      link.curvature = function(_) {
        if (!arguments.length) return curvature;
        curvature = +_;
        return link;
      };
  
      return link;
    };
  
    // Populate the sourceLinks and targetLinks for each node.
    // Also, if the source and target are not objects, assume they are indices.
    function computeNodeLinks() {
      nodes.forEach(function(node) {
        node.sourceLinks = [];
        node.targetLinks = [];
      });
      links.forEach(function(link) {
        var source = link.source,
            target = link.target;
        if (typeof source === "number") source = link.source = nodes[link.source];
        if (typeof target === "number") target = link.target = nodes[link.target];
        source.sourceLinks.push(link);
        target.targetLinks.push(link);
      });
    }
  
    // Compute the value (size) of each node by summing the associated links.
    function computeNodeValues() {
      nodes.forEach(function(node) {
        node.value = Math.max(
          d3.sum(node.sourceLinks, value),
          d3.sum(node.targetLinks, value)
        );
      });
    }
  
    // Iteratively assign the breadth (x-position) for each node.
    // Nodes are assigned the maximum breadth of incoming neighbors plus one;
    // nodes with no incoming links are assigned breadth zero, while
    // nodes with no outgoing links are assigned the maximum breadth.
    function computeNodeBreadths() {
      var remainingNodes = nodes,
          nextNodes,
          x = 0;
  
      while (remainingNodes.length) {
        nextNodes = [];
        remainingNodes.forEach(function(node) {
          node.x = x;
          node.dx = nodeWidth;
          node.sourceLinks.forEach(function(link) {
            nextNodes.push(link.target);
          });
        });
        remainingNodes = nextNodes;
        ++x;
      }
  
      //
      moveSinksRight(x);
      scaleNodeBreadths((size[0] - nodeWidth) / (x - 1));
    }
  
    function moveSourcesRight() {
      nodes.forEach(function(node) {
        if (!node.targetLinks.length) {
          node.x = d3.min(node.sourceLinks, function(d) { return d.target.x; }) - 1;
        }
      });
    }
  
    function moveSinksRight(x) {
      nodes.forEach(function(node) {
        if (!node.sourceLinks.length) {
          node.x = x - 1;
        }
      });
    }
  
    function scaleNodeBreadths(kx) {
      nodes.forEach(function(node) {
        node.x *= kx;
      });
    }
  
    function computeNodeDepths(iterations) {
      var nodesByBreadth = d3.nest()
          .key(function(d) { return d.x; })
          .sortKeys(d3.ascending)
          .entries(nodes)
          .map(function(d) { return d.values; });
  
      //
      initializeNodeDepth();
      resolveCollisions();
      for (var alpha = 1; iterations &gt; 0; --iterations) {
        relaxRightToLeft(alpha *= .99);
        resolveCollisions();
        relaxLeftToRight(alpha);
        resolveCollisions();
      }
  
      function initializeNodeDepth() {
        var ky = d3.min(nodesByBreadth, function(nodes) {
          return (size[1] - (nodes.length - 1) * nodePadding) / d3.sum(nodes, value);
        });
  
        nodesByBreadth.forEach(function(nodes) {
          nodes.forEach(function(node, i) {
            node.y = i;
            node.dy = node.value * ky;
          });
        });
  
        links.forEach(function(link) {
          link.dy = link.value * ky;
        });
      }
  
      function relaxLeftToRight(alpha) {
        nodesByBreadth.forEach(function(nodes, breadth) {
          nodes.forEach(function(node) {
            if (node.targetLinks.length) {
              var y = d3.sum(node.targetLinks, weightedSource) / d3.sum(node.targetLinks, value);
              node.y += (y - center(node)) * alpha;
            }
          });
        });
  
        function weightedSource(link) {
          return center(link.source) * link.value;
        }
      }
  
      function relaxRightToLeft(alpha) {
        nodesByBreadth.slice().reverse().forEach(function(nodes) {
          nodes.forEach(function(node) {
            if (node.sourceLinks.length) {
              var y = d3.sum(node.sourceLinks, weightedTarget) / d3.sum(node.sourceLinks, value);
              node.y += (y - center(node)) * alpha;
            }
          });
        });
  
        function weightedTarget(link) {
          return center(link.target) * link.value;
        }
      }
  
      function resolveCollisions() {
        nodesByBreadth.forEach(function(nodes) {
          var node,
              dy,
              y0 = 0,
              n = nodes.length,
              i;
  
          // Push any overlapping nodes down.
          nodes.sort(ascendingDepth);
          for (i = 0; i &lt; n; ++i) {
            node = nodes[i];
            dy = y0 - node.y;
            if (dy &gt; 0) node.y += dy;
            y0 = node.y + node.dy + nodePadding;
          }
  
          // If the bottommost node goes outside the bounds, push it back up.
          dy = y0 - nodePadding - size[1];
          if (dy &gt; 0) {
            y0 = node.y -= dy;
  
            // Push any overlapping nodes back up.
            for (i = n - 2; i &gt;= 0; --i) {
              node = nodes[i];
              dy = node.y + node.dy + nodePadding - y0;
              if (dy &gt; 0) node.y -= dy;
              y0 = node.y;
            }
          }
        });
      }
  
      function ascendingDepth(a, b) {
        return a.y - b.y;
      }
    }
  
    function computeLinkDepths() {
      nodes.forEach(function(node) {
        node.sourceLinks.sort(ascendingTargetDepth);
        node.targetLinks.sort(ascendingSourceDepth);
      });
      nodes.forEach(function(node) {
        var sy = 0, ty = 0;
        node.sourceLinks.forEach(function(link) {
          link.sy = sy;
          sy += link.dy;
        });
        node.targetLinks.forEach(function(link) {
          link.ty = ty;
          ty += link.dy;
        });
      });
  
      function ascendingSourceDepth(a, b) {
        return a.source.y - b.source.y;
      }
  
      function ascendingTargetDepth(a, b) {
        return a.target.y - b.target.y;
      }
    }
  
    function center(node) {
      return node.y + node.dy / 2;
    }
  
    function value(link) {
      return link.value;
    }
  
    return sankey;
  };</code></pre>
  </div>
  </div>
  </p>
  
  <p>The code works well, but I don't want to use the index of the nodes to create a link. Instead of the index I want to use the name of the nodes.</p>
  
  <p>Can anyone help me?</p>