The Filter Package

Add "joomla/filter": "~1.0" to the require block in your composer.json and then run composer install.

{
	"require": {
		"joomla/filter": "~1.0"
	}
}

Alternatively, you can simply run the following from the command line:

composer require joomla/filter "~1.0"

Note that the Joomla\Language package is an optional dependency and is only required if the application requires the use of OutputFilter::stringURLSafe.