rest_handle_options_request() WordPress Function

function rest_handle_options_request( $response, $handler, $request ) {
	if ( ! empty( $response ) || $request->get_method() !== 'OPTIONS' ) {
		return $response;
	}

	$response = new WP_REST_Response();
	$data     = array();

	foreach ( $handler->get_routes() as $route => $endpoints ) {
		$match = preg_match( '@^' . $route . '$@i', $request->get_route(), $matches );

		if ( ! $match ) {
			continue;
		}

		$args = array();
		foreach ( $matches as $param => $value ) {
			if ( ! is_int( $param ) ) {
				$args[ $param ] = $value;
			}
		}

		foreach ( $endpoints as $endpoint ) {
			// Remove the redundant preg_match() argument.
			unset( $args[0] );

			$request->set_url_params( $args );
			$request->set_attributes( $endpoint );
		}

		$data = $handler->get_data_for_route( $route, $endpoints, 'help' );
		$response->set_matched_route( $route );
		break;
	}

	$response->set_data( $data );
	return $response;
}