feat(isEmail): add whitelist host to isEmail validation (#1920)

closes #1912

README.md

@@ -110,7 +110,7 @@ Validator                               | Description
 **isDecimal(str [, options])**             | check if the string represents a decimal number, such as 0.1, .3, 1.1, 1.00003, 4.0, etc.<br/><br/>`options` is an object which defaults to `{force_decimal: false, decimal_digits: '1,', locale: 'en-US'}`<br/><br/>`locale` determine the decimal separator and is one of `['ar', 'ar-AE', 'ar-BH', 'ar-DZ', 'ar-EG', 'ar-IQ', 'ar-JO', 'ar-KW', 'ar-LB', 'ar-LY', 'ar-MA', 'ar-QA', 'ar-QM', 'ar-SA', 'ar-SD', 'ar-SY', 'ar-TN', 'ar-YE', 'bg-BG', 'cs-CZ', 'da-DK', 'de-DE', 'el-GR', 'en-AU', 'en-GB', 'en-HK', 'en-IN', 'en-NZ', 'en-US', 'en-ZA', 'en-ZM', 'es-ES', 'fa', 'fa-AF', 'fa-IR', 'fr-FR', 'fr-CA', 'hu-HU', 'id-ID', 'it-IT', 'ku-IQ', 'nb-NO', 'nl-NL', 'nn-NO', 'pl-PL', 'pl-Pl', 'pt-BR', 'pt-PT', 'ru-RU', 'sl-SI', 'sr-RS', 'sr-RS@latin', 'sv-SE', 'tr-TR', 'uk-UA', 'vi-VN']`.<br/>**Note:** `decimal_digits` is given as a range like '1,3', a specific value like '3' or min like '1,'.
 **isDivisibleBy(str, number)**          | check if the string is a number that's divisible by another.
 **isEAN(str)**                          | check if the string is an EAN (European Article Number).
-**isEmail(str [, options])**            | check if the string is an email.<br/><br/>`options` is an object which defaults to `{ allow_display_name: false, require_display_name: false, allow_utf8_local_part: true, require_tld: true, allow_ip_domain: false, domain_specific_validation: false, blacklisted_chars: '', host_blacklist: [] }`. If `allow_display_name` is set to true, the validator will also match `Display Name <email-address>`. If `require_display_name` is set to true, the validator will reject strings without the format `Display Name <email-address>`. If `allow_utf8_local_part` is set to false, the validator will not allow any non-English UTF8 character in email address' local part. If `require_tld` is set to false, e-mail addresses without having TLD in their domain will also be matched. If `ignore_max_length` is set to true, the validator will not check for the standard max length of an email. If `allow_ip_domain` is set to true, the validator will allow IP addresses in the host part. If `domain_specific_validation` is true, some additional validation will be enabled, e.g. disallowing certain syntactically valid email addresses that are rejected by GMail. If `blacklisted_chars` receives a string, then the validator will reject emails that include any of the characters in the string, in the name part. If `host_blacklist` is set to an array of strings and the part of the email after the `@` symbol matches one of the strings defined in it, the validation fails.
+**isEmail(str [, options])**            | check if the string is an email.<br/><br/>`options` is an object which defaults to `{ allow_display_name: false, require_display_name: false, allow_utf8_local_part: true, require_tld: true, allow_ip_domain: false, domain_specific_validation: false, blacklisted_chars: '', host_blacklist: [] }`. If `allow_display_name` is set to true, the validator will also match `Display Name <email-address>`. If `require_display_name` is set to true, the validator will reject strings without the format `Display Name <email-address>`. If `allow_utf8_local_part` is set to false, the validator will not allow any non-English UTF8 character in email address' local part. If `require_tld` is set to false, e-mail addresses without having TLD in their domain will also be matched. If `ignore_max_length` is set to true, the validator will not check for the standard max length of an email. If `allow_ip_domain` is set to true, the validator will allow IP addresses in the host part. If `domain_specific_validation` is true, some additional validation will be enabled, e.g. disallowing certain syntactically valid email addresses that are rejected by GMail. If `blacklisted_chars` receives a string, then the validator will reject emails that include any of the characters in the string, in the name part. If `host_blacklist` is set to an array of strings and the part of the email after the `@` symbol matches one of the strings defined in it, the validation fails. If `host_whitelist` is set to an array of strings and the part of the email after the `@` symbol matches none of the strings defined in it, the validation fails. 
 **isEmpty(str [, options])**            | check if the string has a length of zero.<br/><br/>`options` is an object which defaults to `{ ignore_whitespace:false }`.
 **isEthereumAddress(str)**              | check if the string is an [Ethereum](https://ethereum.org/) address using basic regex. Does not validate address checksums.
 **isFloat(str [, options])**            | check if the string is a float.<br/><br/>`options` is an object which can contain the keys `min`, `max`, `gt`, and/or `lt` to validate the float is within boundaries (e.g. `{ min: 7.22, max: 9.55 }`) it also has `locale` as an option.<br/><br/>`min` and `max` are equivalent to 'greater or equal' and 'less or equal', respectively while `gt` and `lt` are their strict counterparts.<br/><br/>`locale` determine the decimal separator and is one of `['ar', 'ar-AE', 'ar-BH', 'ar-DZ', 'ar-EG', 'ar-IQ', 'ar-JO', 'ar-KW', 'ar-LB', 'ar-LY', 'ar-MA', 'ar-QA', 'ar-QM', 'ar-SA', 'ar-SD', 'ar-SY', 'ar-TN', 'ar-YE', 'bg-BG', 'cs-CZ', 'da-DK', 'de-DE', 'en-AU', 'en-GB', 'en-HK', 'en-IN', 'en-NZ', 'en-US', 'en-ZA', 'en-ZM', 'es-ES', 'fr-CA', 'fr-FR', 'hu-HU', 'it-IT', 'nb-NO', 'nl-NL', 'nn-NO', 'pl-PL', 'pt-BR', 'pt-PT', 'ru-RU', 'sl-SI', 'sr-RS', 'sr-RS@latin', 'sv-SE', 'tr-TR', 'uk-UA']`. Locale list is `validator.isFloatLocales`.

src/lib/isEmail.js

@@ -13,6 +13,7 @@ const default_email_options = {
   blacklisted_chars: '',
   ignore_max_length: false,
   host_blacklist: [],
+  host_whitelist: [],
 };
 
 /* eslint-disable max-len */
@@ -99,6 +100,10 @@ export default function isEmail(str, options) {
     return false;
   }
 
+  if (options.host_whitelist.length > 0 && !options.host_whitelist.includes(lower_domain)) {
+    return false;
+  }
+
   let user = parts.join('@');
 
   if (options.domain_specific_validation && (lower_domain === 'gmail.com' || lower_domain === 'googlemail.com')) {

test/validators.js

@@ -344,6 +344,22 @@ describe('Validators', () => {
     });
   });
 
+  it('should validate only email addresses with whitelisted domains', () => {
+    test({
+      validator: 'isEmail',
+      args: [{ host_whitelist: ['gmail.com', 'foo.bar.com'] }],
+      valid: [
+        '[email protected]',
+        '[email protected]',
+      ],
+      invalid: [
+        '[email protected]',
+        '[email protected]',
+        '[email protected]',
+      ],
+    });
+  });
+
   it('should validate URLs', () => {
     test({
       validator: 'isURL',