Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The setAppBadge() method of the WorkerNavigator interface sets a badge on the icon associated with this app. If a value is passed to the method, this will be set as the value of the badge. Otherwise the badge will display as a dot, or other indicator as defined by the platform.
setAppBadge()
setAppBadge(contents)contents OptionalA Number which will be used as the value of the badge. If contents is 0 then the badge will be set to nothing, indicating a cleared badge.
A Promise that resolves with undefined.
InvalidStateError DOMExceptionThrown if the document is not fully active.
SecurityError DOMExceptionThrown if the call was blocked by the same-origin policy.
NotAllowedError DOMExceptionThrown if PermissionStatus.state is not granted.
In the example below an unread count is passed to setAppBadge(). The badge should then display 30.
const unread = 30;
navigator.setAppBadge(unread);