Uncaught ReferenceError - calling a JavaScript function from a Razor v

I am trying to call a function but I am getting - Uncaught ReferenceError: SetNavStateToX not defined.

@Scripts.Render("~/bundles/jquery")
@Styles.Render("~/Content/css")


    @switch (@Session["NavState"])
    {
        case "Exists":
            
Welcome back @Session["UserName"].
            
I hope you are back because you enjoy the forum and blog and what it has to offer.

            @* NOTE: this one works fine. *@
            @**@
        
            

            break;

        default:
            break;
    }