Bootstrap 4 navwalker - multilevel menu

Question

I'm using this nav walker in my Wordpress project. I want to create multilevel menu, for example. What I need to change to get it work? Or maybe is it another walker for BS4 with multilevel menu support?

Menu Item
- Sub menu
-- Sub menu item
-- Sub menu item
Menu Item

Answer 1

1. Add this css

   ul.dropdown-menu li > ul.dropdown-menu{
       left: 100%;
       top: 0;
   }
   
   ul.dropdown-menu li:hover > ul.dropdown-menu, ul.dropdown-menu li:focus > ul.dropdown-menu{
       display: block
   }
   

2. Remove this code && 0 === $depth from class-wp-bootstrap-navwalker.php

   original code:

   if ( isset( $args->has_children ) && $args->has_children && 0 === $depth && $args->depth > 1 ) {
   

   After editing:

   if ( isset( $args->has_children ) && $args->has_children && $args->depth > 1 ) {