What I do for my production apps is. For dev, i simply use all the individual files. For staging, I minify and concatenate and push it to an S3 bucket, and read it directly from there. For production, on CDN, because of caching, I add a version number to my js and css file name. This way I alway s guarantee that the user is using the correct version of my client code. I have grunt tasks to do all of these automatically, and it has worked really well for me.