atom-shell/docs/api/browser/power-monitor.md

power-monitor

The power-monitor module is used to monitor the power state change, you can only use it on the browser side.

An example is:

require('power-monitor').on('suspend', function() {
  console.log('The system is going to sleep');
});

Event: suspend

Emitted when the system is suspending.

Event: resume

Emitted when system is resuming.