Add prependHTTP() to @wordpress/url (#112)

packages/url/README.md

@@ -13,10 +13,13 @@ npm install @wordpress/url --save
 ## Usage
 
 ```JS
-import { addQueryArgs } from '@wordpress/url';
+import { addQueryArgs, prependHTTP } from '@wordpress/url';
 
 // Appends arguments to the query string of a given url
 const newUrl = addQueryArgs( 'https://google.com', { q: 'test' } ); // https://google.com/?q=test
+
+// Prepends 'http://' to URLs that are probably mean to have them
+const actualUrl = prependHTTP( 'wordpress.org' ); // http://wordpress.org
 ```
 
 <br/><br/><p align="center"><img src="https://s.w.org/style/images/codeispoetry.png?1" alt="Code is Poetry." /></p>

packages/url/src/index.js

@@ -4,6 +4,9 @@
 import { parse, format } from 'url';
 import { parse as parseQueryString, stringify } from 'querystring';
 
+const EMAIL_REGEXP = /^(mailto:)?[a-z0-9._%+-]+@[a-z0-9][a-z0-9.-]*\.[a-z]{2,63}$/i;
+const USABLE_HREF_REGEXP = /^(?:[a-z]+:|#|\?|\.|\/)/i;
+
 /**
  * Appends arguments to the query string of the url
  *
@@ -19,3 +22,18 @@ export function addQueryArgs( url, args ) {
 
 	return format( { ...parsedURL, query } );
 }
+
+/**
+ * Prepends "http://" to a url, if it looks like something that is meant to be a TLD.
+ *
+ * @param  {String} url The URL to test
+ *
+ * @return {String}     The updated URL
+ */
+export function prependHTTP( url ) {
+	if ( ! USABLE_HREF_REGEXP.test( url ) && ! EMAIL_REGEXP.test( url ) ) {
+		return 'http://' + url;
+	}
+
+	return url;
+}

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

@@ -1,7 +1,7 @@
 /**
  * Internal Dependencies
  */
-import { addQueryArgs } from '../';
+import { addQueryArgs, prependHTTP } from '../';
 
 describe( 'addQueryArgs', () => {
 	test( 'should append args to an URL without query string', () => {
@@ -25,3 +25,59 @@ describe( 'addQueryArgs', () => {
 		expect( addQueryArgs( url, args ) ).toBe( 'https://andalouses.example/beach?night=false&sun=true&sand=false' );
 	} );
 } );
+
+describe( 'prependHTTP', () => {
+	test( 'should prepend http to a domain', () => {
+		const url = 'wordpress.org';
+
+		expect ( prependHTTP( url ) ).toBe( 'http://' + url );
+	} );
+
+	test( "shouldn't prepend http to an email", () => {
+		const url = 'foo@wordpress.org';
+
+		expect ( prependHTTP( url ) ).toBe( url );
+	} );
+
+	test( "shouldn't prepend http to an absolute URL", () => {
+		const url = '/wordpress';
+
+		expect ( prependHTTP( url ) ).toBe( url );
+	} );
+
+	test( "shouldn't prepend http to a relative URL", () => {
+		const url = './wordpress';
+
+		expect ( prependHTTP( url ) ).toBe( url );
+	} );
+
+	test( "shouldn't prepend http to an anchor URL", () => {
+		const url = '#wordpress';
+
+		expect ( prependHTTP( url ) ).toBe( url );
+	} );
+
+	test( "shouldn't prepend http to a URL that already has http", () => {
+		const url = 'http://wordpress.org';
+
+		expect ( prependHTTP( url ) ).toBe( url );
+	} );
+
+	test( "shouldn't prepend http to a URL that already has https", () => {
+		const url = 'https://wordpress.org';
+
+		expect ( prependHTTP( url ) ).toBe( url );
+	} );
+
+	test( "shouldn't prepend http to a URL that already has ftp", () => {
+		const url = 'ftp://wordpress.org';
+
+		expect ( prependHTTP( url ) ).toBe( url );
+	} );
+
+	test( "shouldn't prepend http to a URL that already has mailto", () => {
+		const url = 'mailto:foo@wordpress.org';
+
+		expect ( prependHTTP( url ) ).toBe( url );
+	} );
+} );