Push handles push notifications for this app.
The push plugin (window.PushNotification).
token: PushToken | undefined
saveToken(token: PushToken, options?: PushSaveTokenOptions): Promise<PushToken>
Register a token with the API.
When a token is saved, you can send push notifications to it. If a user is logged in, the token is linked to them by their ID.
Registers the device with GCM/APNS to get a push token.
After a device is registered, you will likely want to save the token with
saveToken() to the API.
Invalidate the current push token.