path regression (trailing slash is added in 0.5.2)

[chimurai]

Environment

Hi,

Tried to update to 0.5.2 in http-proxy-middleware

Looks like #137 introduced regression in paths?

In this specific test /api is not preserved and is now being proxied differently:
https://github.com/chimurai/http-proxy-middleware/pull/1234/changes#diff-89634a91bb39f03a55c0c5ffa685aa8bc2c807017ae554f83caa4cd25cf50a95R160

The url is now send as /api/ to target server. (with trailing slash)

Reproduction

const app = express()

app.use('/', createProxyMiddleware({
    changeOrigin: true,
    target: `http://localhost:9000/api`,        // <--- configure target with path
}));

app.listen(3000)

before: (0.5.1)
curl http://localhost:3000 -> http://localhost:9000/api

after: (0.5.2)
curl http://localhost:3000 -> http://localhost:9000/api/

                                                       ^ Notice the trailing slash

Describe the bug

Trailing slash is added when target is used with path

---

If I revert the logic from (#137) to the previous, the trailing slash is gone.

function joinURL(base, path) {
	if (!base || base === "/") return path || "/";
  if (!path || path === "/") {     // <---- original
    return base || "/";            // <---- original
  }

  //...
}

Additional context

Recently migrated to httpxy in https://www.npmjs.com/package/http-proxy-middleware

The { target: 'http://[::1]:9000/api' } is quite common pattern to rewrite paths when the proxy is mounted on same or different path in the server.

Logs

[chimurai]

Fix by revert: 5cb386e

Released in: https://github.com/unjs/httpxy/releases/tag/v0.5.3