def nav_link(options = {}, &block)
      c, a = fetch_controller_and_action(options)
      p = options.delete(:params) || {}

      klass = page_active?(c, a, p) ? 'active' : ''


      # Add our custom class into the html_options, which may or may not exist
      # and which may or may not already have a :class key
      o = options.delete(:html_options) || {}
      o[:class] = "#{o[:class]} #{klass}".strip

      if block_given?
        content_tag(:li, capture(&block), o)
      else
        content_tag(:li, nil, o)
      end
    end
def nav_link(options = {}, &block)
      c, a = fetch_controller_and_action(options)
      p = options.delete(:params) || {}

      klass = page_active?(c, a, p) ? 'active' : ''


      # Add our custom class into the html_options, which may or may not exist
      # and which may or may not already have a :class key
      o = options.delete(:html_options) || {}
      o[:class] = "#{o[:class]} #{klass}".strip

      if block_given?
        content_tag(:li, capture(&block), o)
      else
        content_tag(:li, nil, o)
      end
    end
Navigation link helper

 Returns an `li` element with an 'active' class if the supplied
 controller(s) and/or action(s) are currently active. The content of the
 element is the value passed to the block.

 options - The options hash used to determine if the element is "active" (default: {})
           :controller   - One or more controller names to check (optional).
           :action       - One or more action names to check (optional).
           :path         - A shorthand path, such as 'dashboard#index', to check (optional).
           :html_options - Extra options to be passed to the list element (optional).
 block   - An optional block that will become the contents of the returned
           `li` element.

 When both :controller and :action are specified, BOTH must match in order
 to be marked as active. When only one is given, either can match.

 Examples

   # Assuming we're on TreeController#show

   # Controller matches, but action doesn't
   nav_link(controller: [:tree, :refs], action: :edit) { "Hello" }
   # => '<li>Hello</li>'

   # Controller matches
   nav_link(controller: [:tree, :refs]) { "Hello" }
   # => '<li class="active">Hello</li>'

   # Shorthand path
   nav_link(path: 'tree#show') { "Hello" }
   # => '<li class="active">Hello</li>'

   # Supplying custom options for the list element
   nav_link(controller: :tree, html_options: {class: 'home'}) { "Hello" }
   # => '<li class="home active">Hello</li>'

 Returns a list item element String