return function (token?: util.ICancellationToken) {

		const utf8Filter = util.filter(data => /(\/|\\)test(\/|\\).*utf8/.test(data.path));
		const tsFilter = util.filter(data => /\.ts$/.test(data.path));
		const noDeclarationsFilter = util.filter(data => !(/\.d\.ts$/.test(data.path)));

		const input = es.through();
		const output = input
			.pipe(utf8Filter)
			.pipe(bom())
			.pipe(utf8Filter.restore)
			.pipe(tsFilter)
			.pipe(util.loadSourcemaps())
			.pipe(ts(token))
			// .pipe(build ? reloadTypeScriptNodeModule() : es.through())
			.pipe(noDeclarationsFilter)
			.pipe(build ? nls() : es.through())
			.pipe(noDeclarationsFilter.restore)
			.pipe(sourcemaps.write('.', {
				addComment: false,
				includeContent: !!build,
				sourceRoot: options.sourceRoot
			}))
			.pipe(tsFilter.restore)
			.pipe(reporter.end(emitError));

		return es.duplex(input, output);
	};

var createDuplex = function(input, out){
  return es.duplex(input, out);
};