diff --git a/src/backends/backend.js b/src/backends/backend.js
index 2e0350ba..3db54493 100644
--- a/src/backends/backend.js
+++ b/src/backends/backend.js
@@ -102,9 +102,7 @@ class Backend {
       // If this collection has a "filter" property, filter entries accordingly
       .then(loadedCollection => (
         {
-          entries: loadedCollection.entries.filter(
-            entry => (!collectionFilter || entry.data[collectionFilter.get('field')] === collectionFilter.get('value'))
-          ),
+          entries: collectionFilter ? this.filterEntries(loadedCollection, collectionFilter) : loadedCollection.entries
         }
       ));
   }
@@ -249,6 +247,12 @@ class Backend {
     }
     return file.get('fields').map(f => f.get('name')).toArray();
   }
+
+  filterEntries(collection, filterRule) {
+    return collection.entries.filter(entry => (
+      entry.data[filterRule.get('field')] === filterRule.get('value')
+    ));
+  }
 }
 
 export function resolveBackend(config) {