Working compiler in browser.

web/web_command.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:html' show HttpRequest;
+import 'dart:convert' show BASE64;
+
+import 'package:analyzer/file_system/file_system.dart'
+    show ResourceProvider, ResourceUriResolver;
+import 'package:analyzer/file_system/memory_file_system.dart'
+    show MemoryResourceProvider;
+import 'package:analyzer/src/context/cache.dart'
+    show AnalysisCache, CachePartition;
+import 'package:analyzer/src/context/context.dart' show AnalysisContextImpl;
+import 'package:analyzer/src/generated/engine.dart'
+    show AnalysisContext, AnalysisEngine, TimestampedData;
+import 'package:analyzer/src/generated/sdk.dart'
+    show DartSdk, SdkLibrary, SdkLibraryImpl;
+import 'package:analyzer/src/generated/source.dart'
+    show DartUriResolver, Source, SourceFactory, UriKind;
+import 'package:analyzer/src/summary/idl.dart' show PackageBundle;
+import 'package:analyzer/src/summary/summary_sdk.dart' show SummaryBasedDartSdk;
+
+import 'package:args/command_runner.dart';
+
+import 'package:dev_compiler/src/analyzer/context.dart' show AnalyzerOptions;
+import 'package:dev_compiler/src/compiler/compiler.dart'
+    show BuildUnit, CompilerOptions, JSModuleFile, ModuleCompiler;
+
+typedef void MessageHandler(Object message);
+typedef String CompileFn(String dart);
+typedef void OnLoadFn(CompileFn compile);
+
+/// The command for invoking the modular compiler.
+class WebCompileCommand extends Command {
+  get name => 'compile';
+  get description => 'Compile a set of Dart files into a JavaScript module.';
+  final MessageHandler messageHandler;
+  final OnLoadFn onload;
+
+  WebCompileCommand(this.onload, {MessageHandler messageHandler})
+      : this.messageHandler = messageHandler ?? print {
+    CompilerOptions.addArguments(argParser);
+    AnalyzerOptions.addArguments(argParser);
+  }
+
+  @override
+  String run() {
+    var request = new HttpRequest();
+
+    request.onReadyStateChange.listen((_) {
+      if (request.readyState == HttpRequest.DONE &&
+          (request.status == 200 || request.status == 0)) {
+        var response = request.responseText;
+        var sdkBytes = BASE64.decode(response);
+        var result = setUpCompile(sdkBytes);
+        onload(result);
+      }
+    });
+
+    request.open('get', 'dart_sdk.sum');
+    request.send();
+
+    return "";

[Jennifer Messerly, 2016/07/28 05:23:10]

I think you could make this method be "void run()" and skip this return value.

[priscillalee, 2016/07/28 17:15:52]

Done.

+  }
+
+  CompileFn setUpCompile(List<int> sdkBytes) {
+    var resourceProvider = new MemoryResourceProvider();
+    var packageBundle = new PackageBundle.fromBuffer(sdkBytes);
+    var webDartSdk = new SummaryBasedDartSdk.fromBundle(
+        true, packageBundle, resourceProvider);
+
+    var sdkResolver = new DartUriResolver(webDartSdk);
+    var fileResolvers = [new ResourceUriResolver(resourceProvider)];
+
+    var compiler = new ModuleCompiler(
+        new AnalyzerOptions(dartSdkPath: '/dart-sdk'),
+        sdkResolver: sdkResolver,
+        fileResolvers: fileResolvers,
+        resourceProvider: resourceProvider);
+
+    var compilerOptions = new CompilerOptions.fromArguments(argResults);
+
+    var number = 0;
+
+    return (String dart) {
+      //Create a new virtual File that contains the given Dart source.

[Jennifer Messerly, 2016/07/28 05:23:10]

style: add a space after the "//"

[priscillalee, 2016/07/28 17:15:52]

Done.

+      number++;
+      resourceProvider.newFile("/expression$number.dart", dart);
+
+      var unit =
+          new BuildUnit("", "", ["file:///expression$number.dart"], null);
+
+      JSModuleFile module = compiler.compile(unit, compilerOptions);
+      module.errors.forEach(messageHandler);
+
+      if (!module.isValid) throw new CompileErrorException();
+      return module.code;
+    };
+  }
+}
+
+/// Thrown when the input source code has errors.
+class CompileErrorException implements Exception {
+  toString() => '\nPlease fix all errors before compiling (warnings are okay).';
+}