fix(module-loader): null references

src/util/module-loader.ts

@@ -75,24 +75,26 @@ export interface LoadedModule {
  * @hidden
  */
 export function setupPreloadingImplementation(config: Config, deepLinkConfig: DeepLinkConfig, moduleLoader: ModuleLoader): Promise<any> {
-  if (config.getBoolean('preloadModules') && deepLinkConfig && deepLinkConfig.links) {
-    const linksToLoad = deepLinkConfig.links.filter(link => !!link.loadChildren && link.priority !== 'off');
+  if (!deepLinkConfig || !deepLinkConfig.links || !config.getBoolean('preloadModules')) {
+    return Promise.resolve();
+  }
+  const linksToLoad = deepLinkConfig.links.filter(link => !!link.loadChildren && link.priority !== 'off');
+
+  // Load the high priority modules first
+  const highPriorityPromises = linksToLoad
+    .filter(link => link.priority === 'high')
+    .map(link => moduleLoader.load(link.loadChildren));
 
-    // Load the high priority modules first
-    const highPriorityPromises = linksToLoad.filter(link => link.priority === 'high')
+  return Promise.all(highPriorityPromises).then(() => {
+    // Load the low priority modules after the high priority are done
+    const lowPriorityPromises = linksToLoad
+      .filter(link => link.priority === 'low')
       .map(link => moduleLoader.load(link.loadChildren));
 
-    return Promise.all(highPriorityPromises).then(() => {
-      // Load the low priority modules after the high priority are done
-      const lowPriorityPromises = linksToLoad.filter(link => link.priority === 'low')
-        .map(link => moduleLoader.load(link.loadChildren));
-      return Promise.all(lowPriorityPromises);
-    }).catch(err => {
-      console.error(err.message);
-    });
-  } else {
-    return Promise.resolve();
-  }
+    return Promise.all(lowPriorityPromises);
+  }).catch(err => {
+    console.error(err.message);
+  });
 }
 
 /**