Checking for empty layers before checking for conflicts

Author: rustedgrail

lib/order/index.js

@@ -38,6 +38,7 @@ function order(g, opts) {
   let maxRank = util.maxRank(g),
     downLayerGraphs = buildLayerGraphs(g, util.range(1, maxRank + 1), "inEdges"),
     upLayerGraphs = buildLayerGraphs(g, util.range(maxRank - 1, -1, -1), "outEdges");
+
   let layering = (0, _initOrder.default)(g);
   assignOrder(g, layering);
 
@@ -47,6 +48,7 @@ function order(g, opts) {
 
   let bestCC = Number.POSITIVE_INFINITY,
     best;
+
   for (let i = 0, lastBest = 0; lastBest < 4; ++i, ++lastBest) {
     sweepLayerGraphs(i % 2 ? downLayerGraphs : upLayerGraphs, i % 4 >= 2);
     layering = util.buildLayerMatrix(g);

lib/position/bk.js

@@ -70,7 +70,7 @@ function findType1Conflicts(g, layering) {
     });
     return layer;
   }
-  layering.reduce(visitLayer);
+  layering.length && layering.reduce(visitLayer);
   return conflicts;
 }
 function findType2Conflicts(g, layering) {
@@ -107,7 +107,7 @@ function findType2Conflicts(g, layering) {
     });
     return south;
   }
-  layering.reduce(visitLayer);
+  layering.length && layering.reduce(visitLayer);
   return conflicts;
 }
 function findOtherInnerSegmentNode(g, v) {