Question

I am new to ruby on rails. I finally succeeded installing rails on ubuntu 11 and created an app with “rails new myapp”.

But while generating a model with “bundle exec rails generate model Comment user:string user_comment:text” i am getting the following error:

I am clueless for what might have went wrong.

/home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/execjs-1.2.9/lib/execjs/runtimes.rb:47:in `autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/execjs-1.2.9/lib/execjs.rb:5:in `'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/execjs-1.2.9/lib/execjs.rb:4:in `'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `require'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `require'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/coffee-rails-3.1.1/lib/coffee-rails.rb:1:in `require'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/coffee-rails-3.1.1/lib/coffee-rails.rb:1:in `'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `require'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `block (2 levels) in require'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `each'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `block in require'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `each'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `require'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler.rb:122:in `require'
    from /home/pratuat/Documents/rails/railsdemo/config/application.rb:7:in `'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands.rb:21:in `require'
    from /home/pratuat/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands.rb:21:in `'
    from script/rails:6:in `require'
    from script/rails:6:in `'

Answer 1

https://github.com/sstephenson/execjs

You need to choose from that list of runtimes. The easiest I’ve found is therubyracer. Add this to your Gemfile, then do a bundle install.

gem "therubyracer"

After that your model generator should work.