Promise

This gem tries to be a Ruby version of the JavaScript Promises as defined by http://promises-aplus.github.io/promises-spec/ and http://dom.spec.whatwg.org/#promises

Installation

Add this line to your application's Gemfile:

gem 'a-ruby-promise'

And then execute:

$ bundle

Or install it yourself as:

$ gem install a-ruby-promise

Usage

Create a promise:

Promise.new do
  begin
    # do some computation
    value = 42 # result of computation
    fulfill(value)
  rescue Exception => e
    reject(e)
  end
end

Create a new promise which will be rejected if it isn't fulfilled before a timeout period:

def timeout_promise(promise, timeout_in_seconds)
  Promise.new do
    promise.then method(:fulfill)
    Thread.new do
      sleep timeout_in_seconds
      reject "Timeout reached"
    end
  end
end

Contributing

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