Menu Custom Data Attributes Wordpress tag a nav link

menu-custom-data-attributes-wordpress-tag-a-nav-link.php

<?php

/*
 * Add filter attribute 
 * With ACF
 */

add_filter( 'walker_nav_menu_start_el', 'modify_walker_data_attr', 10, 4);

function modify_walker_data_attr( $item_output, $item, $depth, $args )
{

    // I use ACF for adding field to a menu item
    // https://www.advancedcustomfields.com/resources/adding-fields-menu-items/
    $data_hover = get_field('data-hover', $item);

    $old = '<a';
    $new = '<a data-hover="'.$data_hover.'" ';

    $item_output = str_replace($old, $new, $item_output);

    return $item_output;
}