anchor.diff:    '--trust-type-annotations'
   ];
   
  +final _sourceDir = 'tool/npm_template';
  +final _destDir = 'build/npm/';
  +final _dir = new Directory(_destDir);
  +
   @Task('Build non-minified npm package with source map.')
   void npmDebug() {
     _dart2jsArgs
  
positive.code: 
  @Task('Build minified npm package.')
  void npmRelease() {
    _ensureBuild();
    final destDir = 'build/npm/';
    final sourceDir = 'tool/npm_template';
  
    final dir = new Directory(destDir);
    if (dir.existsSync()) {
      dir.deleteSync(recursive: true);
    }
    dir.createSync(recursive: true);
  
    final destination = new File(p.join(destDir, 'gltf_validator.dart.js'));
  
    _replaceVersion();
  
    Dart2js.compile(new File(p.join(sourceDir, 'node_wrapper.dart')),
        outFile: destination, extraArgs: _dart2jsArgs);
  
    _restoreVersion();
  
negative.code: 
  @Task('Build Dart snapshot.')
  void snapshot() {
    new Directory('build').createSync();
  
    _replaceVersion();
    Dart.run('bin/gltf_validator.dart',
  