Before deploying a new version of my app on Heroku, I need to do this in my console (for css and js to work on Heroku): RAILS_ENV=production bundle exec rake assets:precompile.
I just picket this code line from a forum, and I my questions is:
1) Why do I need to do this? 2) Is it possible to implement something more permanent in my Rails code so it does this precompiling automatically (so I don't need to write it manually every time I do some changes in my css or js files)?
1) Why do I need to do this?
There are lot of js files and css file in rails app generally. The above command compress and minified all those files which will reduce the number of requests that browser makes to render a web page. Web browsers are limited in the number of requests that they can make in parallel, so fewer requests can mean faster loading for your application.
2) Is it possible to implement something more permanent in my Rails code so it does this precompiling automatically (so I don't need to write it manually every time I do some changes in my css or js files)?
Yes. Heroku automatically compiles your assets if you dont include public/assets/manifest.yml for rails 3 and in rails 4 it is public/assets/manifest-<md5 hash>.json
Related Answer : Automatically precompile assets before pushing to Heroku
