handle app store url scheme (#438)

* handle app store url scheme

* Update scheme regex

src/utils/is-url.js

@@ -3,8 +3,8 @@ const isURL = require('is-url');
 // Matches anchor (ie: #raptors)
 const ANCHOR_REGEXP = /^#/;
 
-// Matches scheme (ie: tel:, mailto:, data:)
-const SCHEME_REGEXP = /^[a-z]*:/i;
+// Matches scheme (ie: tel:, mailto:, data:, itms-apps:)
+const SCHEME_REGEXP = /^[a-z][a-z0-9\-+.]*:/i;
 
 module.exports = function(url) {
   return isURL(url) || ANCHOR_REGEXP.test(url) || SCHEME_REGEXP.test(url);

test/is-url.js

@@ -0,0 +1,20 @@
+const assert = require('assert');
+const isURL = require('../src/utils/is-url');
+
+describe('isURL', () => {
+  it('should match url', () => {
+    assert(isURL('https://parceljs.org/'));
+  });
+
+  it('should match anchor', () => {
+    assert(isURL('#'));
+    assert(isURL('#foo'));
+  });
+
+  it('should match scheme-only', () => {
+    assert(isURL('tel:'));
+    assert(isURL('https:'));
+    assert(isURL('mailto:'));
+    assert(isURL('itms-apps:'));
+  });
+});