bootstrap v4 basic navigation script for umbraco

bstrap4MainNav.cshtml

@inherits Umbraco.Web.Mvc.UmbracoTemplatePage

@{
		var homeActive = "active";
		var homeUrl = @Model.Content.AncestorOrSelf(1);	
}

<nav class="navbar navbar-expand-lg navbar-light bg-light" id="mainNav">
  		
      			<button type="button" class="navbar-toggler w-100 border-0 text-left" data-toggle="collapse" data-target="#ba-nav" aria-controls="ba-nav" aria-expanded="false" aria-label="Toggle navigation">
        			<span class="navbar-toggler-icon"></span> Menu
      			</button>  
    		
        <div class="collapse navbar-collapse" id="ba-nav">
          	<ul class="navbar-nav mr-auto">
				<li class="nav-item @if(@Model.Content.Id == 1054 || @Model.Content.Id== 1844){@Html.Raw(@homeActive)}"><a href="@homeUrl.Url" class="nav-link"><i class="fa fa-home"></i> @Umbraco.Field("#Home")</a></li>
    			@traverse(@homeUrl)
			</ul>
        </div>
	</div>
</nav>
					
@helper subNodes(IPublishedContent node)
{
			 var items = node.Children.Where(x => x.IsVisible());
				
			 <div class="dropdown-menu" aria-labelledby="navDrop-@node.Id">
        			@foreach (var item in items)
           			{
						var selected = Model.Content.Path.Contains(@item.Id.ToString()) ? "active" : "";
						var navText = item.HasValue("navText") ? item.GetPropertyValue("navText") : item.Name;
							<a class="dropdown-item" href="@item.Url">
								@Html.Raw(@navText)
							</a>
					}
			</div>
}

@helper traverse(IPublishedContent node)
{
    		var maxLevelForSitemap = 2;
    		var items = node.Children.Where("Visible").Where("Level <= " + maxLevelForSitemap);
			
			
			if (items.Any())
    		{
        		foreach (var item in items)
            	{
					var selected = Model.Content.Path.Contains(@item.Id.ToString()) ? "active" : null;
					var dropdown = item.Children().Where("Visible").Count() > 0 ? "dropdown" : "";
					<li class="nav-item @(selected) @(dropdown)">
						@if(@item.Children().Where("Visible").Count() > 0 ){
							<a class="nav-link dropdown-toggle" href="#" id="navDrop-@(item.Id)" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
								@if(@item.HasValue("navText")){
									@Html.Raw(@item.GetPropertyValue("navText"))
								} else {
									@Html.Raw(@item.Name)
								}
							</a>
							@subNodes(item)	
						} else {
							<a href="@item.Url" class="nav-link">
								@if(@item.HasValue("navText")){
									@Html.Raw(@item.GetPropertyValue("navText"))
								} else {
									@item.Name
								}
					   		</a>
						}		
					</li>
				}
			}
					
}