Many core directives rely on the
$animation service to perform DOM modification. This is true whether or not
ngAnimate is a dependency in an application. The directives that use
$animate can be animated with just CSS and do not need to have custom logic implemented. Each core directive has its own DOM-related purpose, which is related to the
$animate function that it calls. Usually, core directives either add and remove elements or add and remove classes to these elements.
The core directives that use
$animate use the service so that the developer does not have to write any extra code to achieve basic animations. These basic animations usually include fading, rotating, blinking, or various other types of fluid movement. The ...