rake assets:precompile for specific JS file

Question

Could I run rake assets:precompile for specific JavaScript file?

Otherwise the full precompile lasts for 5 minutes and makes quick changes in JavaScript files very annoying.

Answer 1

If you wanted to precompile just one file, you could make a custom rake task to do so fairly easy.

namespace :assets do

  desc "compile one js file"

  task :compile_one_file => :environment do
    dest = "#{Rails.root}/vendor/assets/javascripts/compiled/"
    js_asset = "your_jsfile.js"
    File.write(dest + js_asset, Uglifier.compile(Rails.application.assets.find_asset(js_asset).to_s))
  end

end

then from the command line

rake assets:compile_one_file

Hope this helps, I find this useful for vendor js files that I don't change often such as jquery and jquery plugins. That way when im in development it speeds up my page loads keeping the asset pipeline from having to route all the separate requests for my vendor files. It just serves up one minified js file of all my vendor js.