Enumerate mediaDevices empty javascript

I want to select which camera to use. I ve found that exists: enumerateDevices()

https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/enumerateDevices

if (!navigator.mediaDevices || !navigator.mediaDevices.enumerateDevices) {
  console.log("enumerateDevices() not supported.");
  return;
}

// List cameras and microphones.

navigator.mediaDevices.enumerateDevices()
.then(function(devices) {
  devices.forEach(function(device) {
    console.log(device.kind + ": " + device.label +
                " id = " + device.deviceId);
  });
})
.catch(function(err) {
  console.log(err.name + ": " + err.message);
});

I have tried but it doesnt return any camera device.