# File lib/chef/knife/core/object_loader.rb, line 53
        def object_from_file(filename)
          case filename
          when /\.(js|json)$/
            Chef::JSONCompat.from_json(IO.read(filename))
          when /\.rb$/
            r = klass.new
            r.from_file(filename)
            r
          else
            ui.fatal("File must end in .js, .json, or .rb")
            exit 30
          end
        end