WordPress at a glance
function is not described

is_filtered() WC 1.0

Is_filtered - Returns true when filtering products using layered nav or price sliders.

Hooks from the function
Return

true|false. Nothing.

Usage

is_filtered();

Code of is_filtered() WC 5.3.0

<?php
function is_filtered() {
	return apply_filters( 'woocommerce_is_filtered', ( count( WC_Query::get_layered_nav_chosen_attributes() ) > 0 || isset( $_GET['max_price'] ) || isset( $_GET['min_price'] ) || isset( $_GET['rating_filter'] ) ) ); // WPCS: CSRF ok.
}