Only claim "package:" URLs are unsupported on Node

Closes #630

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.17.5
+
+* Don't claim that "package:" URLs aren't supported when they actually are.
+
 ## 1.17.4
 
 * Consistently parse U+000C FORM FEED, U+000D CARRIAGE RETURN, and sequences of

lib/src/visitor/async_evaluate.dart

@@ -27,6 +27,7 @@ import '../extend/extender.dart';
 import '../importer.dart';
 import '../importer/node.dart';
 import '../importer/utils.dart';
+import '../io.dart';
 import '../logger.dart';
 import '../parse/keyframe_selector.dart';
 import '../syntax.dart';
@@ -851,7 +852,7 @@ class _EvaluateVisitor
         if (tuple != null) return tuple;
       }
 
-      if (url.startsWith('package:')) {
+      if (url.startsWith('package:') && isNode) {
         // Special-case this error message, since it's tripped people up in the
         // past.
         throw "\"package:\" URLs aren't supported on this platform.";

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.17.4
+version: 1.17.5-dev
 description: A Sass implementation in Dart.
 author: Dart Team <[email protected]>
 homepage: https://github.com/sass/dart-sass