gistfile1.txt

$ cat big_what.dart 
main() {
  print(0xABADC0DA * 0xABADC0DA);
//= 8296076440540789000 (doubles, javascript)
//#= 8296076440540789156 (bigints)
}
$ dart_release big_what.dart 
8296076440540789156
$ frogsh big_what.dart 
2001308926266292700
$ node obig.dart.app.js 
8296076440540789000
$ frogsh --compile-only --out=big_what.js big_what.dart 
$ node big_what.js 
2001308926266292700
$ cat big_what.js 
//  ********** Library dart:core **************
//  ********** Natives dart:core **************
// ********** Code for Object **************
// ********** Code for BadNumberFormatException **************
function BadNumberFormatException() {}
BadNumberFormatException.prototype.toString = function() {
  return ("BadNumberFormatException: '" + this._s + "'");
}
// ********** Code for top level **************
function print(obj) {
  if (typeof console == 'object') {
    if (obj) obj = obj.toString();
    console.log(obj);
  } else {
    write(obj);
    write('\n');
  }
}
//  ********** Library dart:coreimpl **************
// ********** Code for NumImplementation **************
NumImplementation = Number;
// ********** Code for StringImplementation **************
StringImplementation = String;
StringImplementation.prototype.contains = function(pattern, startIndex) {
  return this.indexOf(pattern, startIndex) >= 0;
}
// ********** Code for top level **************
//  ********** Library big_what **************
// ********** Code for top level **************
function main() {
  print(2001308926266292700/*0xABADC0DA * 0xABADC0DA*/);
}
main();
$