Suppress generation of JsGlobal and JsType code and use window as the default value instead of {} f…

lib/src/codegen/js_codegen.dart

Index: lib/src/codegen/js_codegen.dart
diff --git a/lib/src/codegen/js_codegen.dart b/lib/src/codegen/js_codegen.dart
index 6f135f0d21cad9d566835518470bb9e35b167124..a9d2f5aae71d40a584c65bfa19db4ca94ea7a835 100644
--- a/lib/src/codegen/js_codegen.dart
+++ b/lib/src/codegen/js_codegen.dart
@@ -34,6 +34,11 @@ import 'code_generator.dart';
 // This must match the optional parameter name used in runtime.js
 const String _jsNamedParameterName = r'opt$';
 
+bool _isAnnotationType(Annotation m, String name) => m.name.name == name;
+
+bool _hasAnnotationType(AnnotatedNode node, String name) =>
+    node.metadata.any((annotation) => _isAnnotationType(annotation, name));
+
 class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
   final LibraryInfo libraryInfo;
   final TypeRules rules;
@@ -45,6 +50,7 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
 
   ClassDeclaration currentClass;
   ConstantEvaluator _constEvaluator;
+  bool _containsJsGlobals = false;

[Jennifer Messerly, 2015/03/17 16:39:18]

should this be explicit on the library tag? e.g. library tag declares that it is
describing APIs on JS "window" object:

@JsGlobal("window")
library dom;

That way we aren't hardcoding "window", and we don't need to infer if the code
had a @JsGlobal inside. Like if we removed the "document" accessor, it would be
nice if the dom.js file still worked

[Jacob, 2015/03/17 21:22:44]

Discussed offline. Switched to @JsName here and for JsType and removed JsGlobal.

 
   final _exports = <String>[];
   final _lazyFields = <VariableDeclaration>[];
@@ -80,9 +86,11 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
     }
 
     var name = jsLibraryName(libraryInfo.library);
+    var defaultValue = _containsJsGlobals ? 'window' : '{}';

[Jennifer Messerly, 2015/03/17 16:39:18]

normally we'd do this as an interpolated expression:

var defaultValue = js.call(_containsJsGlobals ? 'window' : '{}');

js.call makes an expression. It'll cache the resulting AST. slightly faster than
interpolating this as a string below

[Jacob, 2015/03/17 21:22:44]

Done.

     return new JS.Program([
       js.statement('var #;', name),
-      js.statement("(function($_EXPORTS) { 'use strict'; #; })(# || (# = {}));",
+      js.statement(
+          "(function($_EXPORTS) { 'use strict'; #; })(# || (# = $defaultValue));",

[Jennifer Messerly, 2015/03/17 16:39:18]

this should be:
"(function($_EXPORTS) { 'use strict'; #; })(# || (# = #));"

[Jacob, 2015/03/17 21:22:44]

Done.

           [body, name, name])

[Jennifer Messerly, 2015/03/17 16:39:18]

[body, name, name, defaultValue]

[Jacob, 2015/03/17 21:22:44]

Done.

     ]);
   }
@@ -231,6 +239,8 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
 
   @override
   JS.Statement visitClassDeclaration(ClassDeclaration node) {
+    if (_hasAnnotationType(node, 'JsType')) return null;
+
     currentClass = node;
 
     var body = <JS.Statement>[];
@@ -914,6 +924,10 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
 
   @override
   visitTopLevelVariableDeclaration(TopLevelVariableDeclaration node) {
+    if (_hasAnnotationType(node, 'JsGlobal')) {
+      _containsJsGlobals = true;

[Jennifer Messerly, 2015/03/17 16:39:18]

per suggestion above, this won't be needed

+      return null;
+    }
     var body = <JS.Statement>[];
 
     for (var field in node.variables.variables) {
@@ -960,8 +974,9 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
           new JS.VariableDeclaration(last.name.name),
           _visit(lastInitializer.target)));
 
-      var result =
-          <JS.Expression>[new JS.VariableDeclarationList('let', variables)];
+      var result = <JS.Expression>[

[Siggi Cherem (dart-lang), 2015/03/17 01:25:36]

DBC - you might need to run pub-ugprade, seems like an old version of the
formatter.

I just noticed this earlier today so I'm sending a CL to pin the formatter to a
precise version to avoid running into this in the future (see
https://codereview.chromium.org/1011003002/)

+        new JS.VariableDeclarationList('let', variables)
+      ];
       result.addAll(_visitList(lastInitializer.cascadeSections));
       _cascadeTarget = savedCascadeTemp;
       return _statement(result.map((e) => new JS.ExpressionStatement(e)));
@@ -1016,8 +1031,9 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
 
   void _flushLibraryProperties(List<JS.Statement> body) {
     if (_properties.isEmpty) return;
-    body.add(js.statement('dart.copyProperties($_EXPORTS, { # });',
-        [_properties.map(_emitTopLevelProperty)]));
+    body.add(js.statement('dart.copyProperties($_EXPORTS, { # });', [
+      _properties.map(_emitTopLevelProperty)
+    ]));
     _properties.clear();
   }
 
@@ -1609,8 +1625,9 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
   @override
   visitListLiteral(ListLiteral node) {
     // TODO(jmesserly): make this faster. We're wasting an array.
-    var list = js.call('new List.from(#)',
-        [new JS.ArrayInitializer(_visitList(node.elements))]);
+    var list = js.call('new List.from(#)', [
+      new JS.ArrayInitializer(_visitList(node.elements))
+    ]);
     if (node.constKeyword != null) {
       list = js.commentExpression('Unimplemented const', list);
     }
@@ -1936,9 +1953,8 @@ class JSGenerator extends CodeGenerator {
     if (options.emitSourceMaps) {
       var outFilename = path.basename(outputPath);
       var printer = new srcmaps.Printer(outFilename);
-      _writeNode(
-          new SourceMapPrintingContext(printer, path.dirname(outputPath)),
-          jsTree);
+      _writeNode(new SourceMapPrintingContext(
+          printer, path.dirname(outputPath)), jsTree);
       printer.add('//# sourceMappingURL=$outFilename.map');
       // Write output file and source map
       var text = printer.text;