diff --git a/src/lib/services/entities-map.service.ts b/src/lib/services/entities-map.service.ts
index 44ee10c..d7d7302 100644
--- a/src/lib/services/entities-map.service.ts
+++ b/src/lib/services/entities-map.service.ts
@@ -10,7 +10,8 @@ export abstract class EntitiesMapService<E extends Entity<I>, I> {
     private readonly _entityChanged$ = new Subject<E>();
     private readonly _entityDeleted$ = new Subject<E>();
 
-    protected constructor(@Inject('ENTITY_PRIMARY_KEY') protected readonly _primaryKey: string) {}
+    protected constructor(@Inject('ENTITY_PRIMARY_KEY') protected readonly _primaryKey: string) {
+    }
 
     get empty(): boolean {
         return this._map.size === 0;
@@ -73,6 +74,7 @@ export abstract class EntitiesMapService<E extends Entity<I>, I> {
     }
 
     replace(entities: E[]) {
+        /** Return true if files were replaced or false if not **/
         const key = this._pluckPrimaryKey(entities[0]);
         const entityIds = entities.map(entity => entity.id);
         const existingEntities = this.get(key).filter(entity => entityIds.includes(entity.id));
@@ -80,10 +82,14 @@ export abstract class EntitiesMapService<E extends Entity<I>, I> {
             const old = existingEntities.find(e => e.id === entity.id);
             return !old || !entity.isEqual(old);
         });
+
         if (newEntities.length) {
             const all = this.get(key).filter(e => !newEntities.map(entity => entity.id).includes(e.id));
             this.set(key, [...all, ...newEntities]);
+            return true;
         }
+
+        return false;
     }
 
     @Validate()