Updated snapshot to be returned on once

Author: auser

lib/firestack.js

@@ -173,7 +173,8 @@ export class Firestack {
 
   off(name) {
     if (this.eventHandlers[name]) {
-      this.eventHandlers[name].forEach(subscription => subscription.remove());
+      this.eventHandlers[name]
+        .forEach(subscription => subscription.remove());
     }
   }
 }

lib/modules/database.js

@@ -117,6 +117,7 @@ class DatabaseRef {
     const {path} = this.dbPath();
     const modifiers = this.dbModifiers();
     return promisify('onOnce', FirestackDatabase)(path, modifiers, evt)
+      .then(({snapshot}) => new DataSnapshot(snapshot))
   }
 
   off(evt) {