Helium::Dependency

Simple dependency inkjection for Ruby object.

Add this line to your application's Gemfile:

gem 'helium-dependency'

And then execute:

$ bundle

Or install it yourself as:

$ gem install helium-dependency

Simply include Helium::Dependency and then define the list of dependencies, together with a block to create default injection. Injected value are already available when the default block is evaluated, so dependencies can reference each other.

class Bike
  include Helium::Dependency

  dependency(:wheel_size) { 26 }
  dependency(:wheels, public: true) { Array.new(2) { Wheel.new(size: wheel_size) } }
end

Bike.new(wheel_size: 20).wheels #=> [#Wheel(@size: 20), #Wheel(@size: 20)]

Injection happens in the class new method before initialize is called, so you can define your own initialization and use dependencies inside it.

class NamedBike < Bike
  def initialize(name)
    @name = "#{name} (#{wheels.map(&:size).join(', ')})"
  end

  attr_reader :name
end

NamedBike.new("Steven").name #=> "Steven (26, 26)"
NamedBike.new("Lil Steven", wheel_size: 16).name #=> "Lil Steven (16, 16)"

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.

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/helium-dependency. 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.

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