Automatically add mailto: to email addresses when linking

packages/format-library/src/link/index.js

@@ -10,7 +10,7 @@ import {
 	removeFormat,
 	slice,
 } from '@wordpress/rich-text';
-import { isURL } from '@wordpress/url';
+import { isURL, isEmail } from '@wordpress/url';
 import { RichTextToolbarButton, RichTextShortcut } from '@wordpress/block-editor';
 
 /**
@@ -47,6 +47,8 @@ export const link = {
 
 			if ( text && isURL( text ) ) {
 				onChange( applyFormat( value, { type: name, attributes: { url: text } } ) );
+			} else if ( text && isEmail( text ) ) {
+				onChange( applyFormat( value, { type: name, attributes: { url: `mailto:${ text }` } } ) );
 			} else {
 				this.setState( { addingLink: true } );
 			}

packages/url/README.md

@@ -188,6 +188,24 @@ _Returns_
 
 -   `boolean`: Whether or not the URL contains the query arg.
 
+<a name="isEmail" href="#isEmail">#</a> **isEmail**
+
+Determines whether the given string looks like an email.
+
+_Usage_
+
+```js
+const isEmail = isEmail( 'hello@wordpress.org' ); // true
+```
+
+_Parameters_
+
+-   _email_ `string`: The string to scrutinise.
+
+_Returns_
+
+-   `boolean`: Whether or not it looks like an email.
+
 <a name="isURL" href="#isURL">#</a> **isURL**
 
 Determines whether the given string looks like a URL.

packages/url/src/index.js

@@ -23,6 +23,22 @@ export function isURL( url ) {
 	return URL_REGEXP.test( url );
 }
 
+/**
+ * Determines whether the given string looks like an email.
+ *
+ * @param {string} email The string to scrutinise.
+ *
+ * @example
+ * ```js
+ * const isEmail = isEmail( 'hello@wordpress.org' ); // true
+ * ```
+ *
+ * @return {boolean} Whether or not it looks like an email.
+ */
+export function isEmail( email ) {
+	return EMAIL_REGEXP.test( email );
+}
+
 /**
  * Returns the protocol part of the URL.
  *

packages/url/src/test/index.test.js

@@ -8,6 +8,7 @@ import { every } from 'lodash';
  */
 import {
 	isURL,
+	isEmail,
 	getProtocol,
 	isValidProtocol,
 	getAuthority,
@@ -53,6 +54,38 @@ describe( 'isURL', () => {
 	} );
 } );
 
+describe( 'isEmail', () => {
+	it( 'returns true when given things that look like an email', () => {
+		const emails = [
+			'simple@wordpress.org',
+			'very.common@wordpress.org',
+			'disposable.style.email.with+symbol@wordpress.org',
+			'other.email-with-hyphen@wordpress.org',
+			'fully-qualified-domain@wordpress.org',
+			'user.name+tag+sorting@wordpress.org',
+			'x@wordpress.org',
+			'wordpress-indeed@strange-wordpress.org',
+			'wordpress@s.wordpress',
+		];
+
+		expect( every( emails, isEmail ) ).toBe( true );
+	} );
+
+	it( 'returns false when given things that don\'t look like an email', () => {
+		const emails = [
+			'Abc.wordpress.org',
+			'A@b@c@wordpress.org',
+			'a"b(c)d,e:f;g<h>i[j\k]l@wordpress.org',
+			'just"not"right@wordpress.org',
+			'this is"not\allowed@wordpress.org',
+			'this\ still\"not\\allowed@wordpress.org',
+			'1234567890123456789012345678901234567890123456789012345678901234+x@wordpress.org',
+		];
+
+		expect( every( emails, isEmail ) ).toBe( false );
+	} );
+} );
+
 describe( 'getProtocol', () => {
 	it( 'returns the protocol part of a URL', () => {
 		expect( getProtocol( 'http://user:password@www.test-this.com:1020/test-path/file.extension#anchor?query=params&more' ) ).toBe( 'http:' );