A Simple jQuery plugin snippets for displaying the sub-menus dropdown

write this on global.js

$.fn.submenu_dropdown = function() {
    return this.find('a.wp-block-navigation-item__content').click(function(index){
	$(this).siblings('ul.wp-block-navigation__submenu-container').toggleClass('submenu-show');
    });
};

$('li.has-child').submenu_dropdown();

write this on global.css

ul.wp-block-navigation__submenu-container {
    display: none !important;
}
	
ul.wp-block-navigation__submenu-container.submenu-show {
    display: block !important;
}