Show the "Favorite" button ONLY to logged in members with post access when using the Favorites Plugin for WordPress

my_pmpro_members_only_favorites.php

<?php
/*
  This recipe restricts display of the "Favorite" button for 
  the Favorites Plugin by Kyle Phillips (https://wordpress.org/plugins/favorites/).
  
  Be sure to turn off the automatic display of the button under Settings > Favorites > Display.
  The button will be shown to logged in members only on content they have access to view.
*/
function my_pmpro_members_only_favorites( $content ) {
	//Don't show the favorites button on PMPro pages 
	$excluded_pages = array(pmpro_getOption('billing_page_id'), pmpro_getOption('account_page_id'), pmpro_getOption('levels_page_id'), pmpro_getOption('checkout_page_id'), pmpro_getOption('confirmation_page_id'));
	
	//Show the favorites button for members only when they have access to the post
	if( function_exists( 'pmpro_has_membership_access' ) && 
		pmpro_has_membership_access(  ) &&
		is_user_logged_in() &&
		//'post' === get_post_type(  ) &&				//add this line to restrict to 'posts' only
		!is_page( $excluded_pages ) ) {
			if( function_exists( 'get_favorites_button' ) ) {
				$content .= get_favorites_button();
			}
	}
	return $content;
}
add_filter( 'the_content', 'my_pmpro_members_only_favorites' );

This recipe is included in the blog post on "Allow Members to Favorite Posts using the Favorites Plugin for WordPress" at Paid Memberships Pro here: https://www.paidmembershipspro.com/allow-members-favorite-posts-using-favorites-plugin-wordpress/