Check if a bit is set (or not) in Dart, compiled to JS, working with >32-bit integers

bitops.dart

import 'dart:math' as math;

void main() {
  final maxUint = 0xffffffff;
  final longRes = maxUint + maxUint;
  print('As Hex   : ' + longRes.toRadixString(16));
  print('As Binary: ' + longRes.toRadixString(2));
  print('Bit 31   : ' + longRes.getBit(31).toString());
  print('Bit 32   : ' + longRes.getBit(32).toString());
}

extension on int {
  int getBit(int n) {
    return n < 32 ? _getBitSmi(n) : _getBitLng(n);
  }
  
  int _logAndLng(int o) {
    const hi = 0x80000000;
    const lo = 0x7fffffff;
    
    final h1 = ~~(this ~/ hi);
    final h2 = ~~(o ~/ hi);
    final l1 = this & lo;
    final l2 = o & lo;
    
    final hr = h1 & h2;
    final lr = l1 & l2;
    return hr * hi + lr;
  }
  
  int _getBitLng(int n) {
    final rhs = math.pow(2, n) as int;
    return _logAndLng(rhs) == 0 ? 0 : 1;
  }
  
  int _getBitSmi(int n) => (this & (1 << n)) == 0 ? 0 : 1;
}