👀 Lookbook 👀

A native development UI for ViewComponent

Gem version Ruby Style Guide Code style: Prettier

Lookbook gives ViewComponent-based projects a ready-to-go development UI for navigating, inspecting and interacting with component previews.

It uses (and extends) the native ViewComponent preview functionality, so you don't need to learn a new DSL or create any extra files to get up and running.

Lookbook uses RDoc/Yard-style comment tags to extend the capabilities of ViewComponent's previews whilst maintaining compatability with the standard preview class format, so you can add or remove Lookbook at any time without having to rework your code.

Lookbook UI

Features

  • Tree-style navigation menu
  • Live nav search/filter
  • Resizable preview window for responsive testing
  • Highlighted preview source code and HTML output
  • Add notes via comments in the preview file (markdown supported)
  • Auto-updating UI when component or preview files are updated (Rails v6.0+ only)
  • Hide, group and rename preview examples using comment tags
  • Fully compatible with standard the ViewComponent preview system

Lookbook demo

If you want to have a quick play with Lookbook, the easiest way is to give the demo app a spin. It's a basic Rails/ViewComponent app with a few test components included to tinker with.

The demo app repo contains instructions on how to get it up and running.

Installing

⚠️ Please note: Lookbook is still in the early stages of development and has not yet been well tested across a wide range of Rails/ViewComponent versions and setups. If you run into any problems please open an issue with as much detail as possible. Thanks! ⚠️

1. Add as a dependency

Add Lookbook to your Gemfile somewhere after the ViewComponent gem. For example:

gem "view_component", require: "view_component/engine"
gem "lookbook"

2. Mount the Lookbook engine

You then need to mount the Lookbook engine (at a path of your choosing) in your routes.rb file:

Rails.application.routes.draw do
  if Rails.env.development?
    mount Lookbook::Engine, at: "/lookbook"
  end
end

The at property determines the root URL that the Lookbook UI will be served at.

If you would like to expose the Lookbook UI in production as well as in development, just remove the if Rails.env.development? condition from around the mount statement.

Then you can start your app as normal and navigate to http://localhost:3000/lookbook (or whatever mount path you specified) to view your component previews in the Lookbook UI.

Usage

You don't need to do anything special to see your ViewComponent previews and examples in Lookbook - just create them as normal and they'll automatically appear in the Lookbook UI. Preview templates, custom layouts and even bespoke preview controllers should all work as you would expect.

If you are new to ViewComponent development, checkout the ViewComponent documentation on how to get started developing your components and creating previews.

Annotating preview files

Lookbook parses Yard-style comment tags in your preview classes to customise and extend the standard ViewComponent preview experience:

# @label Basic Button
class ButtonComponentPreview < ViewComponent::Preview

  # Primary button
  # ---------------
  # This is the button style you should use for most things.
  #
  # @label Primary
  def default
    render ButtonComponent.new do
      "Click me"
    end
  end

  # Secondary button
  # ---------------
  # This should be used for less important actions.
  def secondary
    render ButtonComponent.new(style: :secondary) do
      "Click me"
    end
  end

  # Unicorn button
  # ---------------
  # This button style is still a **work in progress**.
  #
  # @hidden
  def secondary
    render ButtonComponent.new do
      "Click me"
    end
  end

  # @!group More examples

  def short_text
    render ButtonComponent.new do
      "Go"
    end
  end

  def long_text
    render ButtonComponent.new do
      "Click here to do this thing because it's the best way to do it"
    end
  end

  def emoji_text
    render ButtonComponent.new do
      "👀📗"
    end
  end

  # @!endgroup

end

Tags are just strings identified by their @ prefix - for example @hidden. Tags are always placed in a comment above the relevant preview class or example method.

The following Lookbook-specific tags are available for use:

@label <text>

Used to replace the auto-generated navigation label for the item with <text>.

Available for preview classes & example methods.

# @label Preview Label
class FooComponentPreview < ViewComponent::Preview

  # @label Example Label
  def default
  end
end

@hidden

Used to temporarily exclude an item from the Lookbook navigation. The item will still be accessible via it's URL.

Can be useful when a component (or a variant of a component) is still in development and is not ready to be shared with the wider team.

Available for both preview classes & example methods.

# @hidden
class FooComponentPreview < ViewComponent::Preview

  # @hidden
  def default
  end
end

@!group <name> ... @!endgroup

For smaller components, it can often make sense to render a set of preview examples in a single window, rather than representing them as individual items in the navigation which can start to look a bit cluttered.

You can group a set of examples by wrapping them in @!group <name> / @!endgroup tags within your preview file:

class HeaderComponentPreview < ViewComponent::Preview

  def standard
    render Elements::HeaderComponent.new do
      "Standard header"
    end
  end

  # @!group Sizes

  def small
    render Elements::HeaderComponent.new(size: 12) do
      "Small header"
    end
  end

  def medium
    render Elements::HeaderComponent.new(size: 16) do
      "Small header"
    end
  end

  def big
    render Elements::HeaderComponent.new(size: 24) do
      "Small header"
    end
  end

  # @!endgroup

end

The example above would display the Sizes examples grouped together on a single page, rather than as indiviual items in the navigation:

You can have as many groups as you like within a single preview class, but each example can only belong to one group.

Adding notes

All comment text other than tags will be treated as markdown and rendered in the Notes panel for that example in the Lookbook UI.

# @hidden
class ProfileCardComponentPreview < ViewComponent::Preview

  # Profile Card
  # ------------
  # Use the default profile card component whenever you need to represent a user.
  def default
  end
end

Configuration

Lookbook will use the ViewComponent configuration for your project to find and render your previews so you generally you won't need to configure anything separately.

However the following Lookbook-specific config options are also available:

UI auto-refresh

⚠️ UI auto-refresh is only supported in Rails v6.0+

Disable/enable the auto-updating of the Lookbook UI when files change. Enabled by default.

config.lookbook.auto_refresh = false # default is true

By default Lookbook will listen for changes in any preview directories as well as in the components directory itself.

If you wish to add additional paths to listen for changes in, you can use the listen_paths option:

config.lookbook.listen_paths << Rails.root.join('app/other/directory')

Keyboard shortcuts

Lookbook provides a few keyboard shortcuts to help you quickly move around the UI.

  • f - move focus to the nav filter box
  • Esc [when focus is in nav filter box] - Clear contents if text is present, or return focus to the UI if the box is already empty
  • s - Switch to Source tab in the inspector
  • o - Switch to Output tab in the inspector
  • n - Switch to Notes tab in the inspector
  • r - Refresh the preview (useful if using something like Faker to generate randomised data for the preview)
  • w - Open the standalone rendered preview in a new window

Troubleshooting

Blank preview window

Certain setups (for example when using Rack::LiveReload) can cause an issue with the way that the preview iframe displays the rendered component preview (i.e. using the srcdoc attribute to avoid extra requests).

If you are seeing a blank preview window, but the source and output tabs are both displaying code as expected, you can disable the use of the srcdoc attribute using the following configuration option:

config.lookbook.preview_srcdoc = false

Contributing

Lookbook is very much a small hobby/side project at the moment. I'd love to hear from anyone who is interested in contributing but I'm terrible at replying to emails or messages, so don't be surprised if I take forever to get back to you. It's not personal 😜

Developing on a local version of Lookbook

The quickest way to get a development version of Lookbook up and running is to use the lookbook-demo app and link it to a local version of the Lookbook gem:

Initial setup:

  1. Clone this repository somewhere on your machine - git clone [email protected]:allmarkedup/lookbook.git
  2. Also pull down the lookbook-demo repository to your machine
  3. In the Gemfile of the lookbook-demo repository, replace gem "lookbook", '>= 0.1', git: "https://github.com/allmarkedup/lookbook", branch: "main" with gem "lookbook", path: "../path/to/lookbook" (use the path to your local copy of lookbook)
  4. Install dependencies - from the root of the parent project run bundle install

Starting development

  1. From within the lookbook root directory run the comand npm run dev (this will make sure the CSS/JS is recompiled if/when you make changes to the UI)
  2. From within the lookbook-demo root directory run npm run start - this will start a server and build the demo assets

Point your browser to http://localhost:3000/lookbook to see the UI. You can then make and test changes to the Lookbook code in your local copy of lookbook repo. PRs are welcome if you add anything useful :-)

Note that changes to files in the Lookbook lib/ directory will require a server restart in order to have them applied.

Tests

You can run the tests from within the lookbook root directory with the rake test command.

License

The gem is available as open source under the terms of the MIT License.