msaari/wp-amp-tutorial-menu.php

## wp-amp-tutorial-menu.php
<?php
/**
 * Render the Primary Nav Menu
 *
 * Uses amp-sidebar to handle
 * slideout animation.
 *
 * Be sure to include the amp-sidebar component script.
 * Also, rememeber that the amp-sidebar element must be
 * a direct child of the <body>.
 *
 * @action {your custom template action}
 */
function xwp_render_primary_nav() {
	?>
	<amp-sidebar id="site-menu" layout="nodisplay">
		<ul>
			<?php echo wp_kses_post( xwp_clean_nav_menu_items( 'primary' ) ); ?>
			<li on="tap:site-menu.close"><?php esc_html_e( 'Close', 'wp-amp-tutorial' ); ?></li>
		</ul>
	</amp-sidebar>

	<?php // Note that "site-menu" matches the id of the amp-sidebar element. ?>
	<button on='tap:site-menu.toggle'><?php esc_html_e( 'Open Menu', 'wp-amp-tutorial' ); ?></button>
	<?php
}
add_action( '{your custom template action}', 'xwp_render_primary_nav' );

/**
 * Render a menu with clean markup.
 *
 * @param string $location The desired Menu Location.
 *
 * @return string
 */
function xwp_clean_nav_menu_items( $location ) {
	$locations = get_nav_menu_locations();
	if ( empty( $locations[ $location ] ) ) {
		return '';
	}

	$menu = wp_get_nav_menu_object( $locations[ $location ] );
	$menu_items = wp_get_nav_menu_items( $menu->term_id );

	if ( empty( $menu_items ) || ! is_array( $menu_items ) ) {
		return '';
	}

	ob_start();
	foreach ( $menu_items as $key => $menu_item ) :
		$menu_item->menu_item_parent == 0 ? $class = "" : $class = " class='sub' "; ?>
		<li<?php echo $class; ?>><a href="<?php echo esc_url( $menu_item->url ); ?>"><?php echo esc_html( $menu_item->title ); ?></a></li>
	<?php endforeach;
	return ob_get_clean();
}