import 'dart:async'; import 'package:file/file.dart'; import 'package:jael/jael.dart' as jael; import 'package:jael_preprocessor/jael_preprocessor.dart' as jael; Future process( jael.Document doc, Directory dir, errorHandler(jael.JaelError e)) { return jael.resolve(doc, dir, onError: errorHandler, patch: [ (doc, dir, onError) { print(doc.root.children.length); return doc; }, ]); }