Format file size in Dart

Question

How to format a file size in Dart?

Input: 1000000

Expected output: 1 MB

The input could be either an int or a double for ease of use, and the result should be a String with only one decimal.

Answer 1

I made an extension method for this:

extension FileFormatter on num {
  String readableFileSize({bool base1024 = true}) {
    final base = base1024 ? 1024 : 1000;
    if (this <= 0) return "0";
    final units = ["B", "kB", "MB", "GB", "TB"];
    int digitGroups = (log(this) / log(base)).round();
    return NumberFormat("#,##0.#").format(this / pow(base, digitGroups)) +
        " " +
        units[digitGroups];
  }
}

You will need to use the intl package for the NumberFormat class.

You can display bits or bytes using the boolean base64.

Usage:

int myInt = 12345678;
double myDouble = 2546;
print('myInt: ${myInt.readableFileSize(base1024: false)}');
print('myDouble: ${myDouble.readableFileSize()}');

Output:

myInt: 12.3 MB
myDouble: 2.5 kB

Inspired by this SO answer.