EmPromise

Add this line to your application's Gemfile:

gem 'promise_em'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install promise_em

Simple example with one deferrable

EM.run do
  PromiseEm::Promise.new do |resolve, _reject|
    puts 'new promise'
    EM::Timer.new(0.1) { resolve.call('hello') }
  end.then do |arg|
    puts arg
  end.catch do |*error|
    puts error
  end

  EM::Timer.new(0.5) { EM.stop }
end

# new promise
# hello

Example with few deferrable

EM.run do
  PromiseEm::Promise.new do |resolve, _reject|
    puts 'new promise'
    EM::Timer.new(0.1) { resolve.call('hello') }
  end.then do |arg|
    defer = EM::DefaultDeferrable.new
    puts arg
    EM::Timer.new(0.1) { defer.succeed('hello2') }
    defer
  end.then do |arg| 
    puts arg
    raise "error with arg #{arg}"
  end.catch do |*error|
    puts error
  end

  EM::Timer.new(0.5) { EM.stop }
end

# new promise
# hello
# hello2
# error with arg hello2

Run rake to run the tests and rubocop. 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 the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/user1622/em_promise.

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

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