https://mountainheating.com/wp-content/plugins/divi-collapsible-mobile-menu/public/js/script.js?ver=1.4

1( function( $ ) {
2	var CLASS_TOGGLE_ITEM    = 'dcmm-menu-toggle',
3		CLASS_MENU_ENABLED   = 'dcmm-collapsible',
4		CLASS_SUBMENU_OPENED = 'dcmm-visible';
5
6
7	// Sets up the mobile menu to be collapsible
8	function setup_collapsible_submenus() {
9		$( '#mobile_menu' )
10			.addClass( CLASS_MENU_ENABLED )
11			.find( '.menu-item-has-children > a' )
12				// For parent items with no link, make the entire link a toggle click target
13				// NOTE:  Do this first so `off()` does not remove the toggle handler below
14				.filter( '[href="#"]' )
15					.off( 'click' )  // removing Divi's handler that closes the menu
16					.on ( 'click', function( event ) {
17						event.preventDefault();
18						event.stopPropagation();
19
20						$( this ).children( '.' + CLASS_TOGGLE_ITEM ).trigger( 'click' );
21					} )
22					.end()
23				// ...now add the toggle element and handler
24				.append( '<span class="' + CLASS_TOGGLE_ITEM + '"></span>' )
25				.on( 'click', '.' + CLASS_TOGGLE_ITEM, function( event ) {
26					event.preventDefault();
27					event.stopPropagation();
28
29					$( this ).closest( '.menu-item' ).toggleClass( CLASS_SUBMENU_OPENED );
30				} );
31	}
32
33	// Wait until after the Divi mobile menu has been initialized
34	$( window ).on( 'load', function() {
35		setTimeout( function() {
36			setup_collapsible_submenus();
37		}, 700 );
38	} );
39} )( jQuery );