html - Jade: Change active menu item in parent template

Question

I have a navigation bar in my parent jade template and I'd like to highlight the item which is currently in view. So if I'm on the blog page,

ul
  li Home
  li.active Blog
  li Contact Us
  li About

Without copying the navigation bar structure into each child template, is there a way to have the parent template see what page it's extending and apply the active class accordingly?

Answer 1

parent.jade

doctype 5

html
  block link
    -var selected = 'home'; //default

  -var menu = { 'home': '/home', 'blog': '/blog', 'contact': '/contact' };

  body
    nav
      ul
        each val, key in menu
          li
            if selected === key
              a.selected(href=val, title=key)= key
            else
              a(href=val, title=key)= key

child.jade

extends parent

block link
  -var selected = 'blog';