diff --git a/dist/validator.js b/dist/validator.js
index 250d12c..ddbc0b2 100644
--- a/dist/validator.js
+++ b/dist/validator.js
@@ -1814,7 +1814,7 @@ Validator.prototype = {
       if(Array.isArray(path2)){
         path2 = path2[0];
       }
-      const pos = path2.indexOf('*');
+      const pos = path2.indexOf !== undefined ? path2.indexOf('*') : -1;
       if (pos === -1) {
         return path2;
       }
diff --git a/src/validator.js b/src/validator.js
index ce5ba32..07fb397 100755
--- a/src/validator.js
+++ b/src/validator.js
@@ -296,7 +296,7 @@ Validator.prototype = {
       if(Array.isArray(path2)){
         path2 = path2[0];
       }
-      const pos = path2.indexOf('*');
+      const pos = path2.indexOf !== undefined ? path2.indexOf('*') : -1;
       if (pos === -1) {
         return path2;
       }