Question

If you install Ruby on Rails 3.1 the gem execjs gets installed by default. I excluded CoffeeScript, because I thought it needed execjs, but execjs wants to be installed anyway.
Is execjs now a requirement for Ruby on Rails applications or is there a way to exclude this gem from an installation?

Answer 1

If you comment out all gems relating to the asset pipeline from the Gemfile then execjs will not be installed (and this should work fine in production).

# Gems used only for assets and not required
# in production environments by default.
#group :assets do
#  gem 'sass-rails', "  ~> 3.1.0"
#  gem 'coffee-rails', "~> 3.1.0"
#  gem 'uglifier'
#end