Add conversions between Dart's Uri and the JS URL (#365)

Author: nex3

web/CHANGELOG.md

@@ -5,6 +5,7 @@
   don't exist.
 - Fixed generation of variadic arguments to generate 4 optional parameters.
 - Removed all `@Deprecated` members.
+- Added `URL.toDart` and `Uri.toJS` extension methods.
 
 ## 1.1.1
 

web/lib/src/helpers/extensions.dart

@@ -84,3 +84,22 @@ extension XMLHttpRequestGlue on XMLHttpRequest {
     return headers;
   }
 }
+
+extension URLToUri on URL {
+  /// Converts this to a Dart [Uri] object.
+  Uri get toDart => Uri.parse(toString());
+}
+
+extension UriToURL on Uri {
+  /// Converts this to a JavaScript [URL] object.
+  ///
+  /// Throws an [ArgumentError] if this isn't an absolute URL, since [URL] can
+  /// only represent absolute URLs.
+  URL get toJS {
+    try {
+      return URL(toString());
+    } catch (_) {
+      throw ArgumentError.value(this, 'this', '"$this" isn\'t a valid JS URL.');
+    }
+  }
+}

web/test/helpers_test.dart

@@ -134,4 +134,33 @@ void main() {
     // `close` on a `contentWindow` does nothing.
     expect(contentWindow.closed, false);
   });
+
+  test('converts from a JS to a Dart URL', () {
+    final url =
+        URL('https://foo:bar@example.org:1234/path?query#fragment').toDart;
+    expect(url.scheme, equals('https'));
+    expect(url.userInfo, equals('foo:bar'));
+    expect(url.host, equals('example.org'));
+    expect(url.port, equals(1234));
+    expect(url.path, equals('/path'));
+    expect(url.query, equals('query'));
+    expect(url.fragment, equals('fragment'));
+  });
+
+  test('converts from a Dart to a JS URL', () {
+    final url =
+        Uri.parse('https://foo:bar@example.org:1234/path?query#fragment').toJS;
+    expect(url.protocol, equals('https:'));
+    expect(url.username, equals('foo'));
+    expect(url.password, equals('bar'));
+    expect(url.hostname, equals('example.org'));
+    expect(url.port, equals('1234'));
+    expect(url.pathname, equals('/path'));
+    expect(url.search, equals('?query'));
+    expect(url.hash, equals('#fragment'));
+  });
+
+  test('Uri.toJS throws an ArgumentError for a relative URL', () {
+    expect(() => Uri.parse('/path').toJS, throwsArgumentError);
+  });
 }