yankiara/oxygen-pro-menu-mobile-accessibility.js

## oxygen-pro-menu-mobile-accessibility.js
jQuery(document).ready(function($) {

    // Initialize roles and aria attributes
    $('.oxy-pro-menu-list .menu-item-has-children > a').attr('aria-haspopup','true').attr('aria-expanded','false');
    $('.oxy-pro-menu-list .sub-menu').each(function(){
        $(this).attr('aria-label', $(this).prev('a').text());
    });

    if ( $('.oxy-pro-menu-mobile-open-icon').css('display') == 'none' ) {

        // Desktop dropdowns

        // - Set aria-expanded
        // - Open with ENTER or SPACE and close previsouly opened dropdown
        // - Close with ENTER or SPACE or ESCAPE
        // - Close with ESCAPE on child link or with TAB from last child link
        // - Use of LEFT/RIGHT/UP/DOWN to navigate
        $('.oxy-pro-menu-list .menu-item-has-children > a').on('keydown', function(e) {
            if ( e.which == 13 || e.which == 32 ) {
                e.preventDefault();
                if ( $(this).attr('aria-expanded') == 'false' ) {
                    $('.oxy-pro-menu-list > .menu-item-has-children > a').mouseleave().attr('aria-expanded','false');
                    $(this).mouseenter().attr('aria-expanded','true');
                } else {
                    $(this).mouseleave().attr('aria-expanded','false');
                }
            }
            if ( e.which == 27 ) {
                if ( $(this).attr('aria-expanded') == 'true' ) {
                    $(this).mouseleave().attr('aria-expanded','false');
                }
            }
        });
        $('.oxy-pro-menu-list > li > a').on('keydown', function(e) {
            if ( e.which == 37 || e.which == 39 ) { // LEFT or RIGHT
                var $next;
                if ( e.which == 39 )
                    $next = $(this).parent().next('li');
                else
                    $next = $(this).parent().prev('li');
                if ( $next.length == 0 ) {
                    if ( e.which == 39 )
                        $next = $(this).parent().siblings().first();
                    else
                        $next = $(this).parent().siblings().last();
                }
                $next = $next.find('a').first();
                $next.focus();
                if ( $(this).attr('aria-expanded') == 'true' ) {
                    $(this).mouseleave().attr('aria-expanded','false');
                    if ( $next.attr('aria-haspopup') == 'true' )
                        $next.mouseenter().attr('aria-expanded','true');
                }
            }
            if ( e.which == 40 ) { // DOWN
                e.preventDefault();
                var expanded = $(this).attr('aria-expanded');
                if ( expanded && expanded == 'true' ) {
                    var $next = $(this).next('ul').find('li').first().find('a').first();
                    $next.focus();
                } else if ( expanded && expanded == 'false' ) {
                    $(this).mouseenter().attr('aria-expanded','true');
                }
            }
            if ( e.which == 38 ) { // UP
                e.preventDefault();
            }
        });
        $('.oxy-pro-menu-list > .menu-item-has-children > ul > li:last-child > a').on('keydown', function(e) {
            if ( e.which == 9 ) {
                $(this).closest(".menu-item-has-children").find("a").first().mouseleave().attr('aria-expanded','false');
            }
        });
        $('.oxy-pro-menu-list .sub-menu > li > a').on('keydown', function(e) {
            if ( e.which == 37 || e.which == 39 ) { // LEFT or RIGHT
                var $next;
                var $parent = $(this).closest('.menu-item-has-children');
                if ( e.which == 39 )
                    $next = $parent.next('li');
                else
                    $next = $parent.prev('li');
                if ( $next.length == 0 ) {
                    if ( e.which == 39 )
                        $next = $parent.siblings().first();
                    else
                        $next = $parfent.siblings().last();
                }
                $next = $next.find('a').first();
                $next.focus();
                $parent.find('a').first().mouseleave().attr('aria-expanded','false');
                if ( $next.attr('aria-haspopup') == 'true' )
                    $next.mouseenter().attr('aria-expanded','true');
            }
            if ( e.which == 38 || e.which == 40 ) { // UP and DOWN
                e.preventDefault();
                var $next;
                if ( e.which == 38 )
                    $next = $(this).parent().prev('li');
                else
                    $next = $(this).parent().next('li');
                if ( $next.length == 0 ) {
                    if ( e.which == 38 )
                        $next = $(this).parent().siblings().last();
                    else
                        $next = $(this).parent().siblings().first();
                }
                $next.find("a").focus();
            }
            if ( e.which == 27 ) {
                $(this).closest(".menu-item-has-children").find("a").first().mouseleave().attr('aria-expanded','false').focus();
            }
        });

    } else {

        // Mobile

        // Close icon: Set focus on first menu item with <TAB>
        // First menu item: Set focus on close icon with <SHIFT>+<TAB>
        // Dropdowns: Set aria-expanded and close previously opened dropdown when opening new one
        $('.oxy-pro-menu-mobile-close-icon').on('keydown',function(e) { // TAB
            if ( e.which == 9 && !e.shiftKey ) {
                e.preventDefault();
                $('.oxy-pro-menu-list > li:first-child > a').focus();
            }
        });
        $('.oxy-pro-menu-list > li:first-child > a').on('keydown',function(e) {
            if( e.shiftKey && e.which == 9 ) { // SHIFT TAB
                e.preventDefault();
                $('.oxy-pro-menu-mobile-close-icon').focus();
            }
        });
        $('.oxy-pro-menu-list > .menu-item-has-children > a').on('click', function(e) {
            if ( $(this).attr('aria-expanded') == 'false' ) {
                oxygen_pro_menu_toggle_dropdown( $('.oxy-pro-menu-list > .menu-item-has-children > a[aria-expanded="true"]') );
                $('.oxy-pro-menu-list > .menu-item-has-children > a[aria-expanded="true"]').attr('aria-expanded','false');
                $(this).attr('aria-expanded','true');
            } else {
                $(this).attr('aria-expanded','false');
            }
        });

    }

});

## oxygen-pro-menu-mobile-accessibility.php
<?php
/**
 * Replace 'div' menu tag by 'nav'
 * Adds aria-labels
 * Activate SPACE and ENTER on open/close icons
**/
add_filter( 'do_shortcode_tag', function( $output, $tag, $attr ) {

	if( 'oxy-pro-menu' != $tag ) return $output;

	$output = preg_replace( '#^(\s*)<div(.*)</div>(?=.*<script)(.+)$#s', '$1<nav aria-label="Main"$2</nav>$3', $output );
	$output = preg_replace( '#(class="[^"]*oxy-pro-menu-mobile-open-icon)#', 'aria-label="Open menu" role="button" tabindex="0" onkeydown="if(13===event.which||32===event.which){this.click();return false;}" $1', $output );
	$output = preg_replace( '#(class="[^"]*oxy-pro-menu-mobile-close-icon)#', 'aria-label="Close menu" role="button" tabindex="0" onkeydown="if(13===event.which||32===event.which){this.click();return false;}" $1', $output );

	return $output;

}, 10, 3 );