diff --git a/src/lib/isPancard.js b/src/lib/isPancard.js
index ee61104b9..80c630666 100644
--- a/src/lib/isPancard.js
+++ b/src/lib/isPancard.js
@@ -1,5 +1,11 @@
-import assertString from "./util/assertString";
+import assertString from './util/assertString';
 
+/**
+ * Check if str is a valid pan card number
+ *
+ * @param {string} str
+ * @return {boolean}
+ */
 export default function isPancard(str) {
   assertString(str);
   const pancardRegex = /^[A-Z]{5}[0-9]{4}[A-Z]$/;