Guard against index out of bounds errors in View All Nav logic

Author: walmokrani

builder/patternlab.js

@@ -367,7 +367,7 @@ var entity_encoder = new he();
           navViewAllSubItem.patternPartial = "viewall-" + pattern.patternGroup + "-" + pattern.patternSubGroup;
 
           //check if we are moving to a new sub section in the next loop
-          if (pattern.patternSubGroup !== patternlab.patterns[i + 1].patternSubGroup) {
+          if (!patternlab.patterns[i + 1] || pattern.patternSubGroup !== patternlab.patterns[i + 1].patternSubGroup) {
             navItem.navSubItems.push(navViewAllSubItem);
             navItem.navSubItemsIndex.push("View All");
           }