This gem ensures that developers won't forget to add assets to config.assets.precompile while they are developing. An exception will be raised if you include an asset via javascript_include_tag or stylesheet_link_tag, and it doesn't match a filter in config.assets.precompile.

Add this line to your application's Gemfile, in the development group:

group :development do
  gem 'assets_precompile_enforcer'
end

And then execute:

$ bundle

Or install it yourself as:

$ gem install assets_precompile_enforcer

You will need to move your config.assets.precompile += ... setting into config/application.rb, instead of config/environments/production.rb. (This setting needs to be shared across development and production.)

You also need to add the following line to config/environments/development.rb:

# Forces included assets to be added to config.assets.precompile
config.assets.enforce_precompile = true

You can also specify a predicate to be tested when the check is about to be enforced:

# Forces included assets to be added to config.assets.precompile
config.assets.enforce_precompile = ->{ !Konacha || Konacha.config.blank? }

You will need to restart your Rails server whenever you make any changes to config.assets.precompile.

Whenever you call javascript_include_tag or stylesheet_link_tag for an asset that doesn't exist in the config.assets.precompile array, Rails will throw an error in your development environment:

<asset file> must be added to config.assets.precompile, otherwise it won't be precompiled for production!

If you have any assets that you don't want to precompile for production, then you can ignore them:

config.assets.ignore_for_precompile = ['development_helpers.js']

To avoid restarting your server when you change config.assets.precompile, add the following lines to config/application.rb:

# Reload config/assets_precompile when changed
config.assets.original_precompile = config.assets.precompile.dup
config.to_prepare { load 'config/assets_precompile.rb' }
config.watchable_files << 'config/assets_precompile.rb'

Then move your config.assets.precompile settings to a new file at config/assets_precompile.rb:

# Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added)
assets = Rails.application.config.assets
assets.precompile = assets.original_precompile + %w( extra_assets.js )

Now you will be able to make changes to config/assets_precompile.rb without needing to restart your server.

You can also configure a custom error message so that other developers know where to register their missing assets:

config.assets.precompile_error_message_proc = -> asset_file { "#{File.basename(asset_file)} must be added to `config/assets_precompile.rb`, otherwise it won't be precompiled for production!" }

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request