gulp-gzip | Gzip plugin for gulp | Frontend Framework library

You can try to swap between 2 lines in the last gulp task that you have wrotten. Let´s put .pipe(concat('app.css')) before .pipe(sass(...))

Sounds like gzip is working fine, but your browser may not be decoding the compressed file because (I guess) your headers arent set correctly.

You need these:

ngCart does not have a main key in its package.json, nor an index.js at its root, so import can not know what to import. So you need to be a little more explicit in your import statement.

try to replace

import 'ngCart'; //this doesn't import it

by

import 'ngCart/dist/ngCart'; //this should do it ;)

Gzipping a second time won't substantially shrink the already gzipped data, and it may even cause issues with clients not expecting data to be gzipped twice (in fact, I'm surprised to read it worked for you).

You should choose one method, but be aware that if you use the Gulp method (using "pre-compressed" files), you need to make sure that the correct Content-Encoding header is set for those resources, otherwise the client won't know the data is compressed.

Since compression overhead usually is negligible, I would just use the middleware.