Power

tv.power is the power state of an Apple TV. A HomePod has no power capability.

console.log(tv.power.state);

tv.power.on('change', state => {
    console.log('power', state);
});

await tv.power.wake();
await tv.power.sleep();

State

state is a PowerState:

State	Meaning
awake	The Apple TV is on
idle	The Apple TV reports itself idle
screensaver	The screensaver runs
asleep	The Apple TV sleeps
unknown	Companion Link has not reported a state yet

The state comes from Companion Link. Without credentials, or while Companion Link is down, it stays at the last reported value (unknown before the first report and after disconnect()).

The change event

change fires on every report from the Apple TV, including the one each Companion Link connect fetches. Unlike now playing and volume it does not skip equal values. After a real drop, the first change carries the current state. Use it to resync.

Waking and sleeping

wake() and sleep() send the wake and suspend keys over AirPlay, so they work without Companion Link. They throw UnavailableError while AirPlay is down.

A sleeping Apple TV may not answer its AirPlay port at all. When the device looks itself up before a connect attempt, it first knocks on WAKE_PORTS (7000, 3689, 49152, 32498) to wake it. See Connection and recovery.