diff --git a/lib/search-query-parser.js b/lib/search-query-parser.js
index ceadc3f..278b7fe 100644
--- a/lib/search-query-parser.js
+++ b/lib/search-query-parser.js
@@ -11,6 +11,10 @@ exports.parse = function (string, options) {
     options = {};
   }
 
+  if (!string) {
+    string = '';
+  }
+
   // Regularize white spacing
   // Make in-between white spaces a unique space
   string = string.trim().replace(/\s+/g, ' ');