The maxActions attribute of the Notification interface returns the maximum number of actions supported by the device and the User Agent. Effectively, this is the maximum number of elements in Notification.actions array which will be respected by the User Agent.

An integer number which indicates the largest number of notification actions that can be presented to the user by the User Agent and the device.

The following snippet logs the maximum number of supported actions.

const maxActions = Notification.maxActions;
console.log(
  `This device can display at most ${maxActions} actions on each notification.`,
);

• Using the Notifications API
• Notification.actions