crash.log

# Invalid header "User Agent" (hyphen is missing in the middle)
$ curl -v -H "User Agent: pinkytinky" http://localhost:4444

$ npm run proxy-server

> http-proxy-handle-invalid-header@1.0.0 proxy-server
> node proxy-server.js

Proxy server listening on port 4444
node:_http_outgoing:622
    throw new ERR_INVALID_HTTP_TOKEN(label || 'Header name', name);
    ^

TypeError [ERR_INVALID_HTTP_TOKEN]: Header name must be a valid HTTP token ["user agent"]
    at ClientRequest.setHeader (node:_http_outgoing:654:3)
    at new ClientRequest (node:_http_client:286:14)
    at Object.request (node:http:103:10)
    at Array.stream (/home/tien/node-http-proxy-handle-invalid-header/node_modules/http-proxy/lib/http-proxy/passes/web-incoming.js:126:74)
    at ProxyServer.<anonymous> (/home/tien/node-http-proxy-handle-invalid-header/node_modules/http-proxy/lib/http-proxy/index.js:81:21)
    at Server.<anonymous> (/home/tien/node-http-proxy-handle-invalid-header/proxy-server.js:8:9)
    at Server.emit (node:events:514:28)
    at parserOnIncoming (node:_http_server:1143:12)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:119:17) {
  code: 'ERR_INVALID_HTTP_TOKEN'
}

Node.js v20.10.0