import 'dart:io'; extension FSExt on FileSystemEntity { Future deleteIfExists() async { if (await exists()) { await delete(); } } int get size { if (this is File) { return (this as File).lengthSync(); } else if(this is Directory){ var size = 0; for(var file in (this as Directory).listSync()){ size += file.size; } return size; } return 0; } }