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danieldpence / storybook_rails

Native Rails partial previews and testing in Storybook.
MIT License
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storybook_rails

The storybook_rails gem provides a Ruby DSL for writing Storybook stories, allowing you to develop, preview, and test standard Rails view partials in Storybook.

Prior Art

This gem is a fork of ViewComponent::Storybook and has been adapted to work with standard Rails view partials.

Features

Installation

Rails Installation

  1. Add the storybook_rails gem, to your Gemfile: gem 'storybook_rails'
  2. Run bundle install.
  3. Add require "action_view/storybook/engine" to config/application.rb
  4. Add **/*.stories.json to .gitignore

Configure Asset Hosts

If your views depend on Javascript, CSS or other assets served by the Rails application you will need to configure asset_hosts appropriately for your various environments. For local development, do this by adding the following to config/development.rb:

Rails.application.configure do
  ...
  config.action_controller.asset_host =  'http://localhost:3000'
  ...
end

Equivalent configuration will be necessary in config/production.rb or application.rb based you your deployment environments.

Storybook Installation

  1. Add Storybook server as a dev dependedncy. The Storybook Controls addon isn't needed but is strongly recommended 
    yarn add @storybook/server @storybook/addon-controls --dev
  2. Add an NPM script to your package.json in order to start the storybook later in this guide 
    {
 "scripts": {
   "storybook": "start-storybook"
 }
}
  3. Create the .storybook/main.js file to configure Storybook to find the json stories the gem creates. Also configure the Controls addon: 
    module.exports = {
 stories: ['../test/components/**/*.stories.json'],
 addons: [
   '@storybook/addon-controls',
 ],
};

  4. Create the .storybook/preview.js file to configure Storybook with the Rails application url to call for the html content of the stories

    
export const parameters = {
 server: {
   url: `http://localhost:3000/storybook`,
 },
};

Webpacker

If your application uses Webpacker to compile your JavaScript and/or CSS, you will need to modify the default Storybook webpack configuration. Please see the Storybook Webpack config for more information on how to do that.

Here's an example of what that might look like:

// .storybook/main.js

const path = require('path');
// Import the Webpacker webpack environment
const environment = require('../config/webpack/environment');
const { merge } = require('webpack-merge');

module.exports = {
  webpackFinal: async (config, { configType }) => {
    // `configType` has a value of 'DEVELOPMENT' or 'PRODUCTION'
    // You can change the configuration based on that.
    // 'PRODUCTION' is used when building the static version of storybook.
    let envConfig = environment.toWebpackConfig();

    // Tell Webpack to compile an additional entry point, pointing to your Webpacker pack file(s)
    let entries = {
      main: config.entry,
      application: path.resolve(__dirname, '../app/javascript/packs/application.js')
    }

    config.entry = entries

    // Storybook doesn't support .scss out of the box, and we like scss, so...
    // Add a rule to tell Webpack to process .scss files using these loaders
    config.module.rules.push({
      test: /\.scss$/,
      use: ['style-loader', 'css-loader', 'sass-loader'],
      include: path.resolve(__dirname, '../'),
    });

    // merge Webpacker's config with Storybook's Webpack config
    let merged = merge(config, {module: envConfig.module}, {plugins: envConfig.plugins}, {devtool: 'cheap-module-source-map'})

    // Return the altered config
    return config;
  },
};

Optional Nice-To-Haves

Setup File-Watching and Automatically run rake storybook_rails:write_stories_json

For a better developer experience, install your favorite file watching utility, such as chokidar and add a couple scripts to enable automatic regeneration of *.stories.json files when you update *_stories.rb files:

yarn add -D chokidar-cli

In package.json:

{
  ...
  "scripts": {
    "storybook:clean": "find ./test/components/stories -name '*.stories.json' -delete && rm -rf node_modules/.cache/storybook",
    "storybook:start": "yarn storybook:clean && yarn storybook:write-json && start-storybook -p 8081",
    "storybook:write-json": "bundle exec rake storybook_rails:write_stories_json",
    "storybook:watch": "chokidar '**/*_stories.rb' -c 'yarn storybook:write-json'"
  },
  ...
}

Usage

Writing Stories

Suppose our app has a shared app/views/shared/_button.html.erb partial:

<% variant_class_map = {
  primary: "button",
  secondary: "button-secondary",
  outline: "button-outline",
} %>

<button class="<%= variant_class_map[variant.to_sym] %>">
  <%= button_text %>
</button>

We can write a stories describing the _button.html.erb partial:

# test/components/stories/buttons/button_stories.rb

class Buttons::ButtonStories < ActionView::Storybook::Stories
  self.title = "Buttons"

  story(:primary) do
    controls do
      text(:button_text, "Primary")
    end
  end

  story(:secondary) do
    controls do
      text(:button_text, "Secondary")
    end
  end

  story(:outline) do
    controls do
      text(:button_text, "Outline")
    end
  end
end

And a story template to render individual stories:

# test/components/stories/buttons/button_stories.html.erb

<% story_name_class_map = {
    primary: "button",
    secondary: "button-secondary",
    outline: "button-outline"
  } %>

<%= render partial: 'shared/button',
    locals: { variant: story_params[:story_name], button_text: story_params[:button_text] } %>

It's up to you how handle rendering your partials in Storybook, but storybook_rails will look for a view template that matches the story name (buttons/button_stories.html.erb in the example above. In addition, storybook_rails provides a story_params helper which provides quick access to the params and args specified in the story config. You can use these parameters in your view template to render each story dynamically. Or not. It's up to you.

Generating Storybook Files

storybook_rails includes a Rails generator to make it easy to generate the files outlined in the section above.

To generate the files above, we could have done this: bin/rails generate storybook_rails:stories Button primary secondary outline.

For more detail, bin/rails storybook_rails:stories --help.

Generating Storybook Stories JSON

Generate the Storybook JSON stories by running the rake task:

rake storybook_rails:write_stories_json

Start the Rails app and Storybook

In separate shells start the Rails app and Storybook

rails s
yarn start-storybook

Alternatively you can use tools like Foreman to start both Rails and Storybook with one command.

Configuration

By Default storybook_rails expects to find stories in the folder test/components/stories. This can be configured but setting config.storybook_rails.stories_path in config/applicaion.rb. For example, if you're using RSpec you might set the following configuration:

config.storybook_rails.stories_path = Rails.root.join("spec/components/stories")

Troubleshooting

Restarting Storybook Fails

If Storybook fails to load with a cannot get / error, it could be related to this issue. As a workaround, you can update the yarn storybook script to remove the node_modules/.cache/storybook files before Storybook starts:

{
  "scripts": {
    "storybook": "rm -rf node_modules/.cache/storybook && start-storybook"
  }
}

Storybook fails to fetch due to CORS

If the Storybook UI is rendering, but not fetching stories from your Rails server and you see an error in the browser console like this:

Access to fetch at 'http://localhost:3000/storybook/button/primary' from origin 'http://localhost:8081' has been blocked by 
CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, 
set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

Then you probably need to setup CORS. Please see rack-cors for examples.

The Story DSL

🚧 Work in progress... 🚧

Parameters

From the Storybook CSF docs:

Parameters are a set of static, named metadata about a story, typically used to control the behavior of Storybook features and addons.

Using the example parameters configuration for the Backgrounds addon, this is how you could accomplish the same parameters using the parameters method:

class ButtonStories < ActionView::Storybook::Stories
  background_data = {
    default: 'twitter',
    values: [
      { name: 'twitter', value: '#00aced' },
      { name: 'facebook', value: '#3b5998' }
    ]
  }

  parameters( { backgrounds: background_data })

  story(:primary) do
    parameters({ backgrounds: { default: 'facebook'} })

    controls do
      text(:button_text, "Primary")
    end
  end
end

Layout

By default, your stories will render without a layout. This can be customized just like you would normally in a Rails controller, by calling layout "application", at either the class level, the story level, or both.

class Buttons::ButtonStories < ActionView::Storybook::Stories
  self.title = "Buttons"
  layout "application"

  story(:primary) do
    controls do
      text(:button_text, "Primary")
    end
  end

  story(:secondary) do
    controls do
      text(:button_text, "Secondary")
    end
  end

  story(:custom) do
    controls do
      text(:button_text, "Custom")
    end

    layout "custom"
  end
end

Controls

Coming soon... in the meantime, see https://github.com/danieldpence/storybook_rails/tree/main/lib/action_view/storybook/controls.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/danieldpence/storybook_rails. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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

Code of Conduct

Everyone interacting in the storybook_rails project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.