Compressing assets with NGINX in reverse proxy mode - node.js

Question

I'm using NGINX as a reverse proxy in front of a Node.js app. The basic proxy works perfectly fine and I'm able to compress assets on the Node server with compression middleware.
To test if it's possible to delegate the compression task to NGINX, I've disabled the middleware and now I'm trying to gzip with NGINX with the following configuration:
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 300;
server {
listen 80;
## gzip config
gzip on;
gzip_min_length 1000;
gzip_comp_level 5;
gzip_proxied any;
gzip_vary on;
gzip_types text/plain
text/css
text/javascript
image/gif
image/png
image/jpeg
image/svg+xml
image/x-icon;
location / {
proxy_pass http://app:3000/;
proxy_http_version 1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_cache_bypass $http_upgrade;
}
}
}
With this configuration, NGINX doesn't compress the assets. I've tried declaring these in the location context with different options but none of them seems to do the trick.
I couldn't find relevant resources on this so I'm questioning if it could be done this way at all.
Important points:
1- Node and NGINX are on different containers so I'm not serving the static assets with NGINX. I'm just proxying to the node server which is serving these files. All I'm trying to achieve is offload the node server with getting NGINX to do the gzipping.
2- I'm testing all the responses with "Accept-Encoding: gzip" enabled.

Answer 1

Try to add the application/javascript content type:
gzip_types
text/css
text/javascript
text/xml
text/plain
text/x-component
application/javascript
application/json
application/xml
application/rss+xml
font/truetype
font/opentype
application/vnd.ms-fontobject
image/svg+xml;
I took values from this conf H5BP: