Precompile js files in rails

precompile_assets.rb

# use this file in the rails app root directory and run it with
# ruby precompile_assets.rb to see if there is any error in your
# js file assets by using Uglifier. This would save you from running
# rake assets:precompile and using production as env var.
require './config/environment'

JS_PATH = 'app/assets/javascripts/**/*.js'.freeze
Dir[JS_PATH].each do |file_name|
  puts "\n#{file_name}"
  puts Uglifier.compile(File.read(file_name))
end