diff --git a/String/ValidateEmail.js b/String/ValidateEmail.js
index 1e1ace2f1..729685fec 100644
--- a/String/ValidateEmail.js
+++ b/String/ValidateEmail.js
@@ -1,11 +1,22 @@
 /*
-  function that takes a string input and return either it is true of false
-  a valid email address
-  e.g.: mahfoudh.arous@gmail.com -> true
-  e.g.: mahfoudh.arous@helsinki.edu -> true
-  e.g.: mahfoudh.arous.com ->false
+  Function that takes a string input and return either true or false
+  If it is a valid email address
 */
 
+/*
+*  Doctests
+*
+* > validateEmail('mahfoudh.arous@gmail.com')
+*  true
+* > validateEmail('mahfoudh.arous@helsinki.edu')
+*  true
+* > validateEmail('mahfoudh.arous.com')
+*  false
+* > validateEmail('')
+*  ! TypeError
+* > validateEmail(null)
+*  ! TypeError
+*/
 const validateEmail = (str) => {
   if (str === '' || str === null) {
     throw new TypeError('Email Address String Null or Empty.')