class ExecJS::ExternalRuntime

def locate_executable(command)
  commands = Array(command)
  if ExecJS.windows? && File.extname(command) == ""
    ENV['PATHEXT'].split(File::PATH_SEPARATOR).each { |p|
      commands << (command + p)
    }
  end
  commands.find { |cmd|
    if File.executable? cmd
      cmd
    else
      path = ENV['PATH'].split(File::PATH_SEPARATOR).find { |p|
        full_path = File.join(p, cmd)
        File.executable?(full_path) && File.file?(full_path)
      }
      path && File.expand_path(cmd, path)
    end
  }
end