feat(isEmail) extend isEmail validator to enable allow_underscores op…

…tion, allowing successful validation of email addresses containing domains with underscores

src/lib/isEmail.js

@@ -1,12 +1,13 @@
 import assertString from './util/assertString';
 
-import merge from './util/merge';
 import isByteLength from './isByteLength';
 import isFQDN from './isFQDN';
 import isIP from './isIP';
+import merge from './util/merge';
 
 const default_email_options = {
   allow_display_name: false,
+  allow_underscores: false,
   require_display_name: false,
   allow_utf8_local_part: true,
   require_tld: true,
@@ -142,6 +143,7 @@ export default function isEmail(str, options) {
   if (!isFQDN(domain, {
     require_tld: options.require_tld,
     ignore_max_length: options.ignore_max_length,
+    allow_underscores: options.allow_underscores,
   })) {
     if (!options.allow_ip_domain) {
       return false;

test/validators.test.js

@@ -36,6 +36,7 @@ describe('Validators', () => {
         'invalid.com',
         '@invalid.com',
         '[email protected].',
+        'foo@_bar.com',
         'somename@ｇｍａｉｌ.com',
         '[email protected].',
         '[email protected]',
@@ -89,6 +90,16 @@ describe('Validators', () => {
     });
   });
 
+  it('should validate email addresses with underscores in the domain', () => {
+    test({
+      validator: 'isEmail',
+      args: [{ allow_underscores: true }],
+      valid: [
+        'foobar@my_sarisari_store.typepad.com',
+      ],
+      invalid: [],
+    });
+  });
 
   it('should validate email addresses without UTF8 characters in local part', () => {
     test({