diff --git a/escapeRegExp.js b/escapeRegExp.js
index 503a103c7..6c77d42de 100644
--- a/escapeRegExp.js
+++ b/escapeRegExp.js
@@ -22,7 +22,7 @@ const reHasRegExpChar = RegExp(reRegExpChar.source)
 function escapeRegExp(string) {
   return (string && reHasRegExpChar.test(string))
     ? string.replace(reRegExpChar, '\\$&')
-    : string
+    : (string || '')
 }
 
 export default escapeRegExp
diff --git a/test/escapeRegExp.js b/test/escapeRegExp.test.js
similarity index 100%
rename from test/escapeRegExp.js
rename to test/escapeRegExp.test.js