WC Memberships example: check if user is active member of any plan (prior to Memberships 1.4)

wc-memberships-check-active-member-old-versions.php

<?php
/**
 * Modify membership product pricing display for non-members
 * changes pricing display if purchasing is restricted to members;
 * active members will see the price instead of a message
 *
 * (WC Memberships older than v1.4)
 *
 * @param string $price the WC price HTML
 * @return string $price the updated price HTML
 */
function sv_change_member_product_price_display( $price ) {

	// bail if Memberships isn't active
	if ( ! function_exists( 'wc_memberships' ) ) {
		return $price;
	}
	
	// get membership plans
	$plans = wc_memberships_get_membership_plans();
	$active_member = array();

	// check if the member has an active membership for any plan
	foreach ( $plans as $plan ) {
		$active = wc_memberships_is_user_active_member( get_current_user_id(), $plan );
		array_push( $active_member, $active );
	}
	
	// only proceed if the user has no active memberships
	if ( ! in_array( true, $active_member )  ) {
	
		// change price display if purchasing is restricted
		if ( wc_memberships_is_product_purchasing_restricted() ) {
			$price = 'Price for members only';
		} 
	}
	
	return $price;
}
add_filter( 'woocommerce_get_price_html', 'sv_change_member_product_price_display' );
add_filter( 'woocommerce_cart_item_price', 'sv_change_member_product_price_display' );