Update build-layer-graph.js

lib/order/build-layer-graph.js

@@ -1,5 +1,5 @@
-var Graph = require("@dagrejs/graphlib").Graph;
-var util = require("../util");
+let Graph = require("@dagrejs/graphlib").Graph;
+let util = require("../util");
 
 module.exports = buildLayerGraph;
 
@@ -34,12 +34,12 @@ module.exports = buildLayerGraph;
  *       graph is not a multi-graph.
  */
 function buildLayerGraph(g, rank, relationship) {
-  var root = createRootNode(g),
+  let root = createRootNode(g),
     result = new Graph({ compound: true }).setGraph({ root: root })
       .setDefaultNodeLabel(v => g.node(v));
 
   g.nodes().forEach(v => {
-    var node = g.node(v),
+    let node = g.node(v),
       parent = g.parent(v);
 
     if (node.rank === rank || node.minRank <= rank && rank <= node.maxRank) {
@@ -48,7 +48,7 @@ function buildLayerGraph(g, rank, relationship) {
 
       // This assumes we have only short edges!
       g[relationship](v).forEach(e => {
-        var u = e.v === v ? e.w : e.v,
+        let u = e.v === v ? e.w : e.v,
           edge = result.edge(u, v),
           weight = edge !== undefined ? edge.weight : 0;
         result.setEdge(u, v, { weight: g.edge(e).weight + weight });