ExecJS::RuntimeUnavailable error when I start the Rails server

Question

I have created a new Rails application. When I try to start the server I get the following error:

[bathakarai@Project1-CO samp]$ rails server
/home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/script_rails_loader.rb:11: warning: Insecure world writable dir /usr in PATH, mode 040777
/home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/bundler-1.3.4/lib/bundler/runtime.rb:216: warning: Insecure world writable dir /usr in PATH, mode 040777
/home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/execjs-1.4.0/lib/execjs/runtimes.rb:51:in `autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/execjs-1.4.0/lib/execjs.rb:5:in `<module:ExecJS>'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/execjs-1.4.0/lib/execjs.rb:4:in `<top (required)>'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `require'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `<top (required)>'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `require'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `<top (required)>'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/coffee-rails-3.2.2/lib/coffee-rails.rb:1:in `require'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/coffee-rails-3.2.2/lib/coffee-rails.rb:1:in `<top (required)>'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/bundler-1.3.4/lib/bundler/runtime.rb:72:in `require'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/bundler-1.3.4/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/bundler-1.3.4/lib/bundler/runtime.rb:70:in `each'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/bundler-1.3.4/lib/bundler/runtime.rb:70:in `block in require'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/bundler-1.3.4/lib/bundler/runtime.rb:59:in `each'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/bundler-1.3.4/lib/bundler/runtime.rb:59:in `require'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/bundler-1.3.4/lib/bundler.rb:132:in `require'
    from /home/bathakarai/gold/Ruby/Practice/Rails/samp/config/application.rb:7:in `<top (required)>'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands.rb:53:in `require'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands.rb:53:in `block in <top (required)>'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
    from /home/bathakarai/.rvm/gems/ruby-2.0.0-p0/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

How can I fix this error?

Answer 1

If you've just generated a new application, this can come up when the gem therubyracer is commented. It is needed to compile your assets. You can uncomment that or install something like nodejs so you won't need to use the gem in all of your projects.

brew install nodejs
# or
sudo apt-get install nodejs

Answer 2

Try

sudo gem install therubyracer

or

gem install therubyracer

Hope this helps