Merge pull request #396 from RohitPaul0007/patch-39

Update build-layer-graph.js

lib/order/build-layer-graph.js

@@ -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 });