function setup() {

  let device1 = {

    video: {

      deviceId: '25e29efcb66aaf5e4cb6df403e59f92e1f6aaa3ad8cee081028a56a62ef21c7e'

    }

  };

  let device2 = {

    video: {

      deviceId: '3b908dc171bbe7f91469a70ba01afc72fac9ccef601ae881f3effbe260cc8d4a'

    }

  };

  let device3 = {

    video: {

      deviceId: '2dcd9cc7e0e39f10346178cd8d42ffcfd7c73fd05bb98d8562acba5c6b3e7ecf'

    }

  };

​

  let capture1 = createCapture(device1);

  let capture2 = createCapture(device2);

  let capture3 = createCapture(device3);

​

​

}

//some mysterious code to get device ids

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);

  });