add isSemver()

README.md

@@ -135,6 +135,7 @@ Validator                               | Description
 **isOctal(str)**                        | check if the string is a valid octal number.
 **isPort(str)**                         | check if the string is a valid port number.
 **isPostalCode(str, locale)**           | check if the string is a postal code,<br/><br/>(locale is one of `[ 'AD', 'AT', 'AU', 'BE', 'BG', 'BR', 'CA', 'CH', 'CZ', 'DE', 'DK', 'DZ', 'EE', 'ES', 'FI', 'FR', 'GB', 'GR', 'HR', 'HU', 'ID', 'IE' 'IL', 'IN', 'IR', 'IS', 'IT', 'JP', 'KE', 'LI', 'LT', 'LU', 'LV', 'MT', 'MX', 'NL', 'NO', 'NZ', 'PL', 'PR', 'PT', 'RO', 'RU', 'SA', 'SE', 'SI', 'TN', 'TW', 'UA', 'US', 'ZA', 'ZM' ]` OR 'any'. If 'any' is used, function will check if any of the locals match. Locale list is `validator.isPostalCodeLocales`.).
+**isSemver(str)** | Check if the string is a [semantic version number](https://semver.org/). 
 **isSurrogatePair(str)**                | check if the string contains any surrogate pairs chars.
 **isURL(str [, options])**              | check if the string is an URL.<br/><br/>`options` is an object which defaults to `{ protocols: ['http','https','ftp'], require_tld: true, require_protocol: false, require_host: true, require_valid_protocol: true, allow_underscores: false, host_whitelist: false, host_blacklist: false, allow_trailing_dot: false, allow_protocol_relative_urls: false, disallow_auth: false }`.<br/><br/>require_protocol - if set as true isURL will return false if protocol is not present in the URL.<br/>require_valid_protocol - isURL will check if the URL's protocol is present in the protocols option.<br/>protocols - valid protocols can be modified with this option.<br/>require_host - if set as false isURL will not check if host is present in the URL.<br/>allow_protocol_relative_urls - if set as true protocol relative URLs will be allowed.
 **isUppercase(str)**                    | check if the string is uppercase.

src/index.js

@@ -100,6 +100,8 @@ import normalizeEmail from './lib/normalizeEmail';
 
 import isSlug from './lib/isSlug';
 
+import isSemver from './lib/isSemver';
+
 const version = '12.1.0';
 
 const validator = {

src/lib/isSemver.js

@@ -0,0 +1,5 @@
+const reg = /(?<=^v?|\sv?)(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)(?:-(?:[1-9]\d*|[\da-z-]*[a-z-][\da-z-]*)(?:\.(?:[1-9]\d*|[\da-z-]*[a-z-][\da-z-]*))*)?(?:\+[\da-z-]+(?:\.[\da-z-]+)*)?(?=$|\s)/ig;
+
+export default function(str) {
+	return reg.test(str);
+}