How to compress files for transfer to node?

Question

Node.js

I found the koa-compress module , connected it, but the result is not visible. What could be the problem?
The code:

app.use(compress({
  filter: function (content_type) {
  	return /text/i.test(content_type)
  },
  threshold: 2048,
  flush: require('zlib').Z_SYNC_FLUSH
}));

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