With Mountain View you create reusable components for your Rails frontend, while generating a living style guide.
Hey! What is a living style guide? A living style guide is a style guide that is always up-to-date and never falls behind.
Does it generate it automatically? You bet!
Example Style Guide
Add this line to your application's Gemfile:
Mountain View supports Ruby 2.2+ and Rails 4.2+ (although it may work in older versions)
Use the built-in generator to create a new component:
rails generate mountain_view:component header
This will create the following directory structure:
app/ components/ header/ _header.html.erb header.css header.js header.yml header_component.rb # optional
Keep in mind that you can also use
haml, or any other
preprocessors that your app is currently using.
<!-- app/components/header/_header.html.erb --> <div class="header"> <h1>This is a header component with the title: <%= title %></h1> <h3>And subtitle <%= subtitle %></h3> <% if show_links? %> <ul> <% links.each do |link| %> <li><%= link %></li> <% end %> </ul> <% end %> </div>
# app/components/header/header_component.rb class HeaderComponent < MountainView::Presenter properties :title, :subtitle property :links, default:  def title properties[:title].titleize end def show_links? links.any? end end
Including a component class is optional, but it helps avoid polluting your
views and helpers with presenter logic. Public methods in your component class
will be made available to the view, along with any properties you define.
You can also access all properties using the
properties method in your
component class and views. You can even define property defaults.
Using components on your views
You can then call your components on any view by using the following helper:
<%= render_component "header", title: "This is a title", subtitle: "And this is a subtitle" %>
You can also pass a block to a component, for example the following component:
<!-- app/components/header/_header.html.erb --> <div class="header"> <%= properties[:yield] %> </div>
Used in a view like so:
<%= render_component "header" do %> <p>Hello World</p> <% end %>
Would output the following in your view:
<div class="header"> <p>Hello World</p> </div>
You can require all the components CSS and JS automatically by requiring
mountain_view in your main JS and CSS files.
In case you want to add global stylesheets (e.g. reset, bootstrap, a grid system, etc) to your Mountain View components you can do it by calling them with an initializer
#config/initializers/mountain_view.rb MountainView.configure do |config| config.included_stylesheets = ["reset", "bootstrap"] end
//= require mountain_view
You don't need to require those again in your application if you're requiring
mountain_view already, that will cause duplicate CSS.
For SASS mixins, variables, functions, etc (anything that doesn't generate
code), you'd need to explicitly do and
@import in each component stylesheet.
As that doesn't generate extra CSS this won't cause any issues with the
generated CSS, you're only giving that stylesheet access to those definitions.
Adding extra pages to the styleguide
In case you want to add additional pages to the styleguide (e.g grid, code_style) to your living style guide, you can do it by generating them in an initializer
MountainView.configure do |config| config.extra_pages = [:grid, :code_style] end
This will generate the routes and conventional links to the style guide.
To add the views to handle the request.
rails generate mountain_view:extra_pages
Automatically generated Style Guide
A style guide will be automatically generated. This style guide never falls behind and it reflects your components in their latest version.
Setting up the style guide
- Add the following line to your
mount MountainView::Engine => "/mountain_view"
- Create stubs for your components. These stubs will be the examples in the style guide.
- :title: "Aspen Snowmass" :description: "Aspen Snowmass is a winter resort complex located in Pitkin County in western Colorado in the United States. Owned and operated by the Aspen Skiing Company it comprises four skiing/snowboarding areas on four adjacent mountains in the vicinity of the towns of Aspen and Snowmass Village." :link: "http://google.com" :image_url: "http://i.imgur.com/QzuIJTo.jpg" :data: - :title: "Elevation" :number: '7879ft' - :title: "Depth" :number: '71"' - :title: "Sunset on the Mountain" :description: "Three major ranges of the Alps – the Northern Calcareous Alps, Central Alps, and Southern Calcareous Alps – run west to east through Austria. The Central Alps, which consist largely of a granite base, are the largest and highest ranges in Austria." :link: "http://google.com"
Example Style Guide
To override the path used within the mountain_view engine, set the
#config/initializers/mountain_view.rb MountainView.configure do |config| config.styleguide_path = "my-style-guide" end
Rendering a large amount of partials in a request can lead to a performance bottleneck, usually this is caused by the parsing and rendering of template code such as ERB or HAML.
Via a Mountain View component you can render your HTML without touching a template parsing engine, which is super performant! To do this, you'll need to override
render(context, &block) method, which is inherited from
For example, if you had a component called
blank_state with the Erb of:
<!-- app/components/blank_state/_blank_state.html.erb --> <div class="blank-state <%= properties[:class] %>"></div>
You'd override the
render method in
blank_state_component.rb like so:
# app/components/blank_state/blank_state_component.rb class BlankStateComponent < MountainView::Presenter properties :class # Override the inherited render method to not read partials from the file system. def render(context, &block) # context is the view we've being rendered from, so it has all Rails helpers context.content_tag(:div, '', class: [ 'blank-state', properties[:class] ].compact.join(' ')) end end
Anecdotally, a request which had to render 50 partials and took a whopping 2000ms was reduced to 200ms using this technique.
See the contributing guide.