### Describe the bug

https://github.com/developer-choi/axios-error-report

TypeError is occurred (in 1.6.6 version)

<img width="184" alt="image" src="https://github.com/axios/axios/assets/51902362/1f7f6e7f-8c8b-4ef7-9854-5c08f572d58b">

<img width="171" alt="image" src="https://github.com/axios/axios/assets/51902362/36042439-a071-485e-b696-9f2c01849759">

### To Reproduce

https://github.com/developer-choi/axios-error-report

### Code snippet

_No response_

### Expected behavior

_No response_

### Axios Version

1.6.6

### Adapter Version

_No response_

### Browser

CHROME

### Browser Version

120.0.6099.225

### Node.js Version

20.11.0

### OS

Window 11
test/unit/adapters/http.js
res.on('data', function (data) {
            body += data;
          });
          res.on('end', function () {
            response.setHeader('Content-Type', 'text/html; charset=UTF-8');
            response.end(body + '1234');
          });
        });
      }).listen(4000, function () {
        // s
        process.env.http_proxy = 'http://localhost:4000/';
        process.env.no_proxy = 'foo.com, ,bar.net , quix.co';
        axios.get('http://localhost:4444/').then(function (res) {
          assert.equal(res.data, '45671234', 'should use proxy for domains not in no_proxy');
          done();
        }).catch(done);
      });
    });
  });
  it('should support HTTP proxy auth', function (done) {
    server = http.createServer(function (req, res) {
      res.end();
    }).listen(4444, function () {
      proxy = http.createServer(function (request, response) {
        var parsed = url.parse(request.url);
        var opts = {
          host: parsed.hostname,
          port: parsed.port,
          path: parsed.path
        };