$ npm install --save express
$ npm install --save-dev @types/express
</pre>
*index.ts
<pre>
import * as functions from 'firebase-functions';
import * as express from 'express';
const app: express.Express = express();
const router: express.Router = express.Router()
app.use(router);
router.get('/test', (req, res) => {
res.send('TEST!');
});
export const api = functions.https.onRequest(app);
</pre>