Is there a way to determine when you are in the simulator or on device programmatically?

You can make use of process.env.NODE_ENV to achieve this. It returns 'development' when in the simulator and 'production' when on device.

if (process.env.NODE_ENV ==='development') {
  //run this in simulator
  console.log('simulator');
}
else{
  // run this on device
  console.log('device');
}