Babel + Schmooze + Sprockets

Bring Babel 6 to Ruby on Rails.

Add this line to your application's Gemfile:

gem "babel-schmooze-sprockets"

And then execute:

$ bundle

Or install it yourself as:

$ gem install babel-schmooze-sprockets

Include the following directive to your main file (e.g. application.js), before anything is loaded:

//= require babel

This will load external-helpers and polyfill.

You can manually load each of those files too:

//= require babel/external-helpers
//= require babel/polyfill

By default, this is what you get:

• AMD modules
• ES2015 preset
• Additional Babel plugins
  • transform-async-to-generator
  • transform-es2015-modules-amd
  • transform-es3-member-expression-literals
  • transform-es3-property-literals
  • transform-function-bind

If you try to load a module exported with ES6 module system using require you'll notice that you have to call .default() on the returned object. This is due to a change on Babel 6.

So, if you're exporting a module like the following

// app/assets/javascripts/lib/boot.es6
export default function boot() {
  // do something
}

this is how you'll have to call:

// app/assets/javascripts/application.js
//= require almond/almond
//= require_dir ./lib
//= require_dir ./application
//= require_self

require(["lib/boot"], function(boot) {
  boot.default();
});

Schmooze only allows one root directory; this means that you'll have to install all plugins locally if you want to use any other plugin not included by this gem.

Assuming you have a package.json file, you can install the default plugins with the following command:

npm install --save-dev \
  babel-core \
  babel-plugin-add-module-exports \
  babel-plugin-transform-async-to-generator \
  babel-plugin-transform-es2015-modules-amd \
  babel-plugin-transform-es3-member-expression-literals \
  babel-plugin-transform-es3-property-literals \
  babel-plugin-transform-function-bind babel-preset-es2015

Then you can install your custom plugin with npm install --save-dev <your custom plugin>.

You'll also have to redefine Sprocket's Babel initialization. Create a file at config/initializers/babel.rb; the following example extends the default configuration:

Rails.application.config.assets.configure do |env|
  processor = BabelSchmoozeSprockets::BabelProcessor.new({
    root_dir: File.expand_path(Rails.root.to_s),
    options: {
      presets: BabelSchmoozeSprockets::BabelProcessor::DEFAULT_PRESETS,
      plugins: BabelSchmoozeSprockets::BabelProcessor::DEFAULT_PLUGINS + ["your-custom-plugin"]
    }
  })

  env.register_transformer "application/ecmascript-6", "application/javascript", processor
end

You may configure the presets and plugins lists as you wish.

Make sure you require babel-polyfill in your main file (e.g. application.js) by adding:

//= require babel

// or

//= require babel/polyfill

• Using ES2015 with Asset Pipeline on Ruby on Rails.

After checking out the repo, run bin/setup to install dependencies. Then, run rake test 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.

To update NPM packages before releasing a new version, just run ./bin/update-npm-deps.

Bug reports and pull requests are welcome on GitHub at https://github.com/fnando/babel-schmooze-sprockets. 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.

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