extension SizeString on num { String get sizeString { var size = toDouble(); if (size < 1000000) { size = size / 1000; size = (size * 10).round() / 10; return '${size.toString()} KB'; } else if (size < 1000000000) { size = size / 1000000; size = (size * 10).round() / 10; return '${size.toString()} MB'; } else { size = size / 1000000000; size = (size * 10).round() / 10; return '${size.toString()} GB'; } } }