WordPress at a glance
function is not described

Automattic\WooCommerce\Admin

PageController::is_registered_page() public WC 1.0

Returns true if we are on a page registed with this controller.

{} It's a method of the class: PageController{}

Return

true|false. Nothing.

Usage

$PageController = new PageController();
$PageController->is_registered_page();

Code of PageController::is_registered_page() WC 5.2.2

<?php
public function is_registered_page() {
	$current_page = $this->get_current_page();

	if ( false === $current_page ) {
		$is_registered_page = false;
	} else {
		$is_registered_page = isset( $current_page['js_page'] ) && $current_page['js_page'];
	}

	/**
	 * Whether or not the current page was registered with this controller.
	 *
	 * Used to determine if this is a JS-powered WooCommerce Admin page.
	 *
	 * @param boolean       $is_registered_page True if the current page was registered with this controller.
	 * @param array|boolean $current_page The registered page data or false if not identified.
	 */
	return apply_filters( 'woocommerce_navigation_is_registered_page', $is_registered_page, $current_page );
}