acts like concat?

[yocontra]

Seems overly complex - shouldnt this just be applied to each file that passes through not buffering it?

[azproduction]

I used gulp-concat as a primer while developing gulp-autopolyfiller. And actually it does not buffer files: https://github.com/azproduction/gulp-autopolyfiller/blob/master/lib/index.js#L54
polyfiller.add() scans for polyfills only without buffering a code.

[yocontra]

Ah I see how this works now - it outputs a new file with the polyfills in it after all files have passed through. You should document that in the README so people don't have to look through the code

[azproduction]

Done, thanks!

[yocontra]

What do you think about inserting a new file into the stream with the polyfills instead of overwriting the whole stream with one file? That way you can pipe all of your JS files into this, then concat and uglify and whatever else further down the stream

[azproduction]

At the very beginning I had that idea of appending polyfills file to the stream. But then I decided that it is better to reduce input from autopolyfiller stream.
So you can generate just polyfills without filtering out your files from stream, and the basic polyfill-concat-uglify is also possible using event-stream.merge.