Angular universal on Firebase hosting serving locally

In Angular Universal generation, the seed code suggests this line to provide the root baseUrl in server.ts:

res.render('index', { req, providers: [{ provide: APP_BASE_HREF, useValue: req.baseUrl }] });

That works on nodejs, and it works when you deploy firebase to your hosting. But it does not work when you serve locally, because req.baseUrl gives a non empty string. All the links you add to your page will be prepended to the full function local path: project_name/us-central1/function_name/, on server side. So clicking any link would yeild to a 404 in Angular, or if you are not handling it "Error: Uncaught (in promise): Error: Cannot match any routes. URL Segment:"

Changing the value used to "" would break the initial root page as well.

After a lot of tug and war, in the function index.js, I decided to keep the nodejs listener to port 5000, while serving firebase.

const universal = require(`./server.js`);

exports.ssr = functions.https.onRequest(universal.server);

// keep this when serving from local
universal.server.listen('5000', function (err) {
	if (err) {
		console.log(err);
		return;
	}

});

Now serving works. And remotely works fine.