anchor.diff:    static const String cmdName = 'compile';
     CompileCommand({bool verbose = false})
         : super(cmdName, 'Compile Dart to various formats.', verbose) {
  -    addSubcommand(CompileJSCommand(
  -      verbose: verbose,
  -    ));
  +    addSubcommand(CompileJSCommand(verbose: verbose));
       addSubcommand(CompileSnapshotCommand(
         commandName: CompileSnapshotCommand.jitSnapshotCmdName,
         help: 'to a JIT snapshot.',
  
positive.code: import 'dart:async';
  import 'dart:io';
  
  import 'package:dart2native/generate.dart';
  import 'package:front_end/src/api_prototype/compiler_options.dart'
      show Verbosity;
  
negative.code: class CompileJSCommand extends CompileSubcommandCommand {
    static const String cmdName = 'js';
  
    /// Accept all flags so we can delegate arg parsing to dart2js internally.
    @override
    final ArgParser argParser = ArgParser.allowAnything();
  
    CompileJSCommand({bool verbose})
        : super(cmdName, 'Compile Dart to JavaScript.', verbose);
  
    @override
    String get invocation => '${super.invocation} <dart entry point>';
  
    @override
    FutureOr<int> run() async {
      if (!Sdk.checkArtifactExists(sdk.dart2jsSnapshot)) return 255;
  
      final librariesPath = path.absolute(sdk.sdkPath, 'lib', 'libraries.json');
  
      if (!Sdk.checkArtifactExists(librariesPath)) return 255;
  
      VmInteropHandler.run(
          sdk.dart2jsSnapshot,
          [
            '--libraries-spec=$librariesPath',
            '--cfe-invocation-modes=compile',
            ...argResults.arguments,
          ],
  