From 47f9ab366372f3a9dd8408bd79e3eda4a36b3e83 Mon Sep 17 00:00:00 2001
From: Brian Soumakian <bsoumakian@gmail.com>
Date: Sat, 8 Apr 2017 03:25:04 -0700
Subject: [PATCH] fix null/undefined references

---
 src/util/module-loader.ts | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/src/util/module-loader.ts b/src/util/module-loader.ts
index 9e2db848a7..1d83e3bcc8 100644
--- a/src/util/module-loader.ts
+++ b/src/util/module-loader.ts
@@ -78,23 +78,17 @@ export interface LoadedModule {
  * @hidden
  */
 export function setupPreloadingImplementation(config: Config, deepLinkConfig: DeepLinkConfig, moduleLoader: ModuleLoader) {
-  if (config.getBoolean('preloadModules')) {
+  if (config.getBoolean('preloadModules') && deepLinkConfig && deepLinkConfig.links) {
       const linksToLoad = deepLinkConfig.links.filter(link => !!link.loadChildren && link.priority !== 'off');
 
       // Load the high priority modules first
-      const highPriorityPromises = linksToLoad.map(link => {
-        if (link.priority === 'high') {
-          return moduleLoader.load(link.loadChildren);
-        }
-      });
+      const highPriorityPromises = linksToLoad.filter(link => link.priority === 'high')
+        .map(link => moduleLoader.load(link.loadChildren));
 
       Promise.all(highPriorityPromises).then(() => {
         // Load the low priority modules after the high priority are done
-        const lowPriorityPromises = linksToLoad.map(link => {
-          if (link.priority === 'low') {
-            return moduleLoader.load(link.loadChildren);
-          }
-        });
+        const lowPriorityPromises = linksToLoad.filter(link => link.priority === 'low')
+          .map(link => moduleLoader.load(link.loadChildren));
         return Promise.all(lowPriorityPromises);
       }).catch(err => {
         console.error(err.message);