OptionalappToken?: stringOptionalattachment?: { data?: string | File; type?: string }Optionalhtml?: booleanOptionalmessage?: stringOptionalpriority?: { callback?: string; expire?: number; level?: number; retry?: number }Optionalsound?: stringOptionaltimestamp?: DateOptionaltitle?: stringThe title of the message.
Optionalurl?: { title?: string; url?: string }The URL to open when the notification is clicked.
Optionaltitle?: stringThe title of the URL to be displayed.
Optionalurl?: stringThe URL itself.
Optionalusers?: { devices?: string[]; name?: string; token?: string }[]
The message to send.