readFromFile method
Reads from a file and returns the content on the form of a String or Uint8List.
Before reading, it checks whether the file exists or not.
Implementation
Future<dynamic> readFromFile(
final String fileFolder,
final String fileName, {
final bool byteMode = false,
}) async {
final _file = await _openFile(fileFolder, fileName);
return byteMode ? await _file.readAsBytes() : await _file.readAsString();
}