docs: improve isEmail option documentation

README.md

@@ -106,7 +106,7 @@ 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` determines 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', 'eo', '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 is divisible by another.
 **isEAN(str)**                          | check if the string is an [EAN (European Article Number)][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, allow_underscores: 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, email addresses without a 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 or regexp, 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 or regexp, and the part of the email after the `@` symbol matches none 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 or falls back to `{ allow_display_name: false, require_display_name: false, allow_utf8_local_part: true, require_tld: true, allow_ip_domain: false, allow_underscores: false, domain_specific_validation: false, blacklisted_chars: '', ignore_max_length: false, host_blacklist: [], host_whitelist: [] }`.<br/><br/>`allow_display_name` - if set to true, the validator will also match `Display Name <email-address>`.<br/>`require_display_name` - if set to true, the validator will reject strings without the format `Display Name <email-address>`.<br/>`allow_utf8_local_part` - if set to false, the validator will not allow any non-English UTF-8 character in the email address' local part.<br/>`require_tld` - if set to false, email addresses without a TLD in their domain will also be matched.<br/>`ignore_max_length` - if set to true, the validator will not check the standard max length of an email, the local part, the domain, or domain labels.<br/>`allow_ip_domain` - if set to true, the validator will allow IP addresses in the host part, including bracket-wrapped IP literals.<br/>`allow_underscores` - if set to true, the validator will allow underscores in the domain part.<br/>`domain_specific_validation` - if set to true, the validator will enable additional provider-specific validation, currently including Gmail/Googlemail local-part rules.<br/>`blacklisted_chars` - if set to a string, the validator will reject emails whose local part contains any character in the string. The string is used as a RegExp character class fragment, so RegExp-special characters should be escaped.<br/>`host_blacklist` - if set to an array of strings or RegExp objects, and the lower-cased host after the `@` symbol matches any entry, validation fails.<br/>`host_whitelist` - if set to a non-empty array of strings or RegExp objects, and the lower-cased host after the `@` symbol matches none of the entries, 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][Ethereum] address. 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` determines 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', 'eo', '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

@@ -6,6 +6,43 @@ import isFQDN from './isFQDN';
 import isIP from './isIP';
 import merge from './util/merge';
 
+/**
+ * @typedef {string|RegExp} EmailHostMatcher
+ */
+
+/**
+ * Options supported by isEmail.
+ *
+ * Every property is optional. When a property is omitted or set to undefined,
+ * isEmail falls back to the value described for that property.
+ *
+ * @typedef {Object} IsEmailOptions
+ * @property {boolean} [allow_display_name=false] - Accept
+ *   `Display Name <email-address>` input.
+ * @property {boolean} [require_display_name=false] - Require
+ *   `Display Name <email-address>` input.
+ * @property {boolean} [allow_utf8_local_part=true] - Allow UTF-8 characters
+ *   in the local part before the `@` symbol.
+ * @property {boolean} [require_tld=true] - Require the domain to include a
+ *   top-level domain unless an allowed IP domain is supplied.
+ * @property {boolean} [allow_ip_domain=false] - Allow the domain to be an IP
+ *   address, including bracket-wrapped IP literals.
+ * @property {boolean} [allow_underscores=false] - Allow underscores in the
+ *   domain part.
+ * @property {boolean} [domain_specific_validation=false] - Apply additional
+ *   provider-specific checks, currently including Gmail username rules.
+ * @property {string} [blacklisted_chars] - Defaults to ''. Reject local parts
+ *   containing any character from this RegExp character class fragment.
+ * @property {boolean} [ignore_max_length=false] - Skip standard email,
+ *   local-part, domain, and domain-label length checks.
+ * @property {EmailHostMatcher[]} [host_blacklist] - Defaults to []. Reject
+ *   emails whose lower-cased host matches one of these strings or regular
+ *   expressions.
+ * @property {EmailHostMatcher[]} [host_whitelist] - Defaults to []. Require
+ *   the lower-cased host to match one of these strings or regular expressions
+ *   when non-empty.
+ */
+
 const default_email_options = {
   allow_display_name: false,
   allow_underscores: false,
@@ -32,7 +69,8 @@ const defaultMaxEmailLength = 254;
 
 /**
  * Validate display name according to the RFC2822: https://tools.ietf.org/html/rfc2822#appendix-A.1.2
- * @param {String} display_name
+ * @param {string} display_name
+ * @returns {boolean} whether the display name is valid.
  */
 function validateDisplayName(display_name) {
   const display_name_without_quotes = display_name.replace(/^"(.+)"$/, '$1');
@@ -61,6 +99,13 @@ function validateDisplayName(display_name) {
   return true;
 }
 
+/**
+ * Check if a string is an email address.
+ *
+ * @param {string} str - The string to validate.
+ * @param {IsEmailOptions} [options] - Optional validation settings.
+ * @returns {boolean} whether the string is a valid email address.
+ */
 export default function isEmail(str, options) {
   assertString(str);
   options = merge(options, default_email_options);