app/views/includes/header.pug
nav.navbar.navbar-expand-md.navbar-dark.fixed-top.bg-dark
a.navbar-brand(href='/') Your App
button.navbar-toggler(type='button' data-toggle='collapse' data-target='#navbarCollapse' aria-controls='navbarCollapse' aria-expanded='false' aria-label='Toggle navigation')
span.navbar-toggler-icon
#navbarCollapse.collapse.navbar-collapse
ul.navbar-nav.mr-auto
li(class=isActive('/') ? 'active nav-item' : 'nav-item')
a.nav-link(href="/" title="Home") Home