npm install osx-screensaver usb-detection

const osxScreensaver = require('osx-screensaver'),
     usbDetect = require('usb-detection'),
     key = {};

usbDetect.find(function(err, devices) {
   devices.forEach(function(device) {
      if (device.manufacturer == "Yubico") {
         key.vid = device.vendorId;
         key.pid = device.productId;
         console.log('found', device, err)
         listen(); // listen for usb removal
      }
   })
});

function listen(){
   usbDetect.on(`remove:${key.vid}:${key.pid}`, function(device) {
      console.log('remove', device);
      osxScreensaver().then(() => {
         console.log('Screensaver started');
      });
   });
}