Using shelljs on Windows and storing the output of a process

I am trying to use shelljs (https://github.com/arturadib/shelljs) for a project I am working on, it works like a charm on Unix based systems but once I try to use it on Windows, I am able to launch a process but I am totally unable to get the output of that process. The documentation mentioned that any of the ways below to get output should work but none of them do on Windows, any suggestions?

var version = exec('node --version', {silent:true}).output;

var child = exec('some_long_running_process', {async:true});
child.stdout.on('data', function(data) {
  /* ... do something with data ... */
});

exec('some_long_running_process', function(code, output) {
  console.log('Exit code:', code);
  console.log('Program output:', output);
});