Node.js socket hang up when agent is present - node.js

Question

I have the following setup:
Client => Proxy server => Origin Server
I'm using the following Node.js libraries for each of these pieces, respectively:
isomorphic-fetch => http-proxy => http
Here's a gist of the setup in two files, one for each of the servers and one for the client: https://gist.github.com/headquarters/850cbb199ff397c6da56fb8d86113a7e
To run this locally, run node server.js in one shell and node fetch.js in another shell.
With the servers running, if I go to http://localhost:8818 in a browser, I get the sample response {"a":"b"}, so that's working. If I go to http://localhost:9818, I also get that response, so the proxying appears to be working fine. However, if I run DEBUG=* node fetch.js, which includes the HTTP proxy agent, the request fails (see output at https://gist.github.com/headquarters/850cbb199ff397c6da56fb8d86113a7e#file-failure-txt).
Without the agent property, the fetch command works fine on the command line. How do I go about debugging this socket hang up error?

Answer 1

Turns out I didn't read the https-proxy-agent docs closely enough. This line was a bit confusing: An HTTP(s) proxy http.Agent implementation for HTTPS--the PROXY itself can be either HTTP or HTTPS, but the origin server has to be HTTPS for this flavor of proxy-agent. For an HTTP origin server, I had to use http-proxy-agent. Thus, the socket hang up was probably coming from https.Agent trying to access an HTTP endpoint. It worked when I switched to http-proxy-agent.