Implement URL.canParse() (#491)

Author: charpeni

js/URL.js

@@ -52,4 +52,14 @@ whatwgUrl.revokeObjectURL = function revokeObjectURL(url) {
   // Do nothing.
 };
 
+whatwgUrl.canParse = function canParse(url, base) {
+  try {
+    // eslint-disable-next-line no-new
+    new URL(url, base);
+    return true;
+  } catch {
+    return false;
+  }
+};
+
 export const URL = whatwgUrl;

js/__tests__/URL-test.js

@@ -1,6 +1,6 @@
 import {URL} from '../URL';
 
-describe('URL', function () {
+describe('URL', () => {
   it('should pass Mozilla Dev Network examples', () => {
     const a = new URL('/', 'https://developer.mozilla.org');
     expect(a.href).toBe('https://developer.mozilla.org/');
@@ -61,4 +61,22 @@ describe('URL', function () {
       'https://facebook.github.io/react-native/img/header_logo.png',
     );
   });
+
+  describe('URL.canParse', () => {
+    it('should return true for valid URLs', () => {
+      expect(URL.canParse('https://example.com')).toBe(true);
+      expect(URL.canParse('ftp://example.com')).toBe(true);
+      expect(URL.canParse('mailto:example@example.com')).toBe(true);
+      expect(
+        URL.canParse('/en-US/docs', 'https://developer.mozilla.org/'),
+      ).toBe(true);
+    });
+
+    it('should return false for invalid URLs', () => {
+      expect(URL.canParse('invalid-url')).toBe(false);
+      expect(URL.canParse('http://')).toBe(false);
+      expect(URL.canParse('ftp://')).toBe(false);
+      expect(URL.canParse('//', 'https://developer.mozilla.org/')).toBe(false);
+    });
+  });
 });