int bytesToInteger(List<int> bytes)

Converts bytes into fixed-size integer. bytes length should be at least 32.

var l = new List<int>.generate(32, (int i) => i + i); // [0, ..., 60, 62]
bytesToInteger(l); // 28149809252802682310...81719888435032634998129152

Source

int bytesToInteger(List<int> bytes) {
  num value = 0;
  bytes = bytes.sublist(0, 32);
  for (var i = 0; i < bytes.length; i++) {
    value += bytes[i] * pow(bits, i);
  }
  ;
  return value.toInt();
}