diff --git a/lib/Parser.js b/lib/Parser.js
index 90465e4..ad2d027 100644
--- a/lib/Parser.js
+++ b/lib/Parser.js
@@ -329,7 +329,7 @@ function parseESearch(text, literals) {
     key = r[i].toLowerCase();
     val = r[i + 1];
     if (key === 'all')
-      val = val.split(',');
+      val = val.toString().split(',');
     attrs[key] = val;
   }