Shutdown, restart, logoff, sleep, hibernate, lock computer, battery power

Use class computer.

computer.shutdown(); //shutdown
computer.shutdown(restart: true); //reboot
computer.logoff(); //logoff (sign out)
computer.sleep(); //sleep
computer.sleep(hibernate: true); //hibernate
computer.lockOrSwitchUser(); //lock

Or run shutdown.exe.

run.console("shutdown.exe", "/s /t 0"); //shutdown
run.console("shutdown.exe", "/s /f /t 0"); //shutdown, force
run.console("shutdown.exe", "/r /t 0"); //reboot
run.console("shutdown.exe", "/r /f /t 0"); //reboot, force
run.console("shutdown.exe", "/l"); //log off
run.console("shutdown.exe", "/h"); //hibernate

On Windows 10 can use the Win+X menu.

keys.send("Win+X ^u"); //show popup menu with shutdown options

Is the computer running on battery?

if (computer.isOnBattery) print.it("on battery");