$ ionic cordova plugin add cordova-plugin-badge
$ npm install @awesome-cordova-plugins/badge
The essential purpose of badge numbers is to enable an application to inform its users that it has something for them — for example, unread messages — when the application isn’t running in the foreground.
Android Note: Badges have historically only been a feature implemented by third party launchers and not visible unless one of those launchers was being used (E.G. Samsung or Nova Launcher) and if enabled by the user. As of Android 8 (Oreo), notification badges were introduced officially to reflect unread notifications. This plugin is unlikely to work as expected on devices running Android 8 or newer. Please see the local notifications plugin docs for more information on badge use with notifications.