Update cross-count.js

lib/order/cross-count.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var zipObject = require("../util").zipObject;
+let zipObject = require("../util").zipObject;
 
 module.exports = crossCount;
 
@@ -21,8 +21,8 @@ module.exports = crossCount;
  * This algorithm is derived from Barth, et al., "Bilayer Cross Counting."
  */
 function crossCount(g, layering) {
-  var cc = 0;
-  for (var i = 1; i < layering.length; ++i) {
+  let cc = 0;
+  for (let i = 1; i < layering.length; ++i) {
     cc += twoLayerCrossCount(g, layering[i-1], layering[i]);
   }
   return cc;
@@ -32,26 +32,26 @@ function twoLayerCrossCount(g, northLayer, southLayer) {
   // Sort all of the edges between the north and south layers by their position
   // in the north layer and then the south. Map these edges to the position of
   // their head in the south layer.
-  var southPos = zipObject(southLayer, southLayer.map((v, i) => i));
-  var southEntries = northLayer.flatMap(v => {
+  let southPos = zipObject(southLayer, southLayer.map((v, i) => i));
+  let southEntries = northLayer.flatMap(v => {
     return g.outEdges(v).map(e => {
       return { pos: southPos[e.w], weight: g.edge(e).weight };
     }).sort((a, b) => a.pos - b.pos);
   });
 
   // Build the accumulator tree
-  var firstIndex = 1;
+  let firstIndex = 1;
   while (firstIndex < southLayer.length) firstIndex <<= 1;
-  var treeSize = 2 * firstIndex - 1;
+  let treeSize = 2 * firstIndex - 1;
   firstIndex -= 1;
-  var tree = new Array(treeSize).fill(0);
+  let tree = new Array(treeSize).fill(0);
 
   // Calculate the weighted crossings
-  var cc = 0;
+  let cc = 0;
   southEntries.forEach(entry => {
-    var index = entry.pos + firstIndex;
+    let index = entry.pos + firstIndex;
     tree[index] += entry.weight;
-    var weightSum = 0;
+    let weightSum = 0;
     while (index > 0) {
       if (index % 2) {
         weightSum += tree[index + 1];