Highlight link to current page
Often to improve your navigation UI (user experience), you will want to mark the link to current page “active”:
2023 Update
Use active_link_to
instead of link_to
to apply classes underline font-bold
to links in your app.
# app/helpers/application_helper.rb
def active_link_to(text = nil, path = nil, **options, &)
link = block_given? ? text : path
options[:class] = class_names(options[:class], 'underline font-bold') if current_page?(link)
if block_given?
link_to(link, options, &)
else
link_to text, path, options
end
end
class_names
that we are using was introduced in Rails 6.1
active_link_to
works with both inline link_to
and block:
<%= active_link_to "Posts", posts_path %>
<%= active_link_to posts_path do %>
Posts
<% end %>
Writing tests for active_link_to
:
# test/helpers/application_helper_test.rb
class ApplicationHelperTest < ActionView::TestCase
test 'active_link_to' do
def current_page?(link)
true
end
assert_equal(
active_link_to('Home', static_pages_pricing_path),
link_to('Home', static_pages_pricing_path, class: "active")
)
def current_page?(link)
false
end
assert_equal(
active_link_to('Home', static_pages_pricing_path),
link_to('Home', static_pages_pricing_path)
)
end
end
Original approach:
The simple way to do it (assuming a bootstrap navbar):
<li class="<%= 'active fw-bold' if current_page?(root_path) %> nav-item">
<%= link_to "Homepage", root_path, class: 'nav-link' %>
</li>
or if you want to add some fancy fontawesome:
<li class="<%= 'active fw-bold' if current_page?(root_path) %> nav-item">
<%= link_to root_path, class: 'nav-link' do %>
<i class="fa fa-home"></i>
Homepage
<% end %>
</li>
however when you have a lot of links, your code will look “dirty”.
To make it look cleaner, you can add the following lines to application_helper.rb
:
def active_link_to(name, path)
content_tag(:li, class: "#{'active fw-bold' if current_page?(path)} nav-item") do
link_to name, path, class: "nav-link"
end
end
end
def deep_active_link_to(path)
content_tag(:li, class: "#{'active fw-bold' if current_page?(path)} nav-item") do
link_to path, class: "nav-link" do
yield
end
end
end
def deep_active_link_to_dropdown_item(path)
content_tag(:li) do
link_to path, class: "#{'active fw-bold' if current_page?(path)} dropdown-item" do
yield
end
end
end
this way you can write links like this
<%= active_link_to "homepage" root_path %>
or
<%= deep_active_link_to root_path do %>
<i class="fa fa-home"></i>
Homepage
<% end %>