firebase cloud function for sapper doing SSR with cache control

index.ts

// @ts-nocheck    TODO: remove once there are typings in place
// Start writing Firebase Functions
// https://firebase.google.com/docs/functions/typescript
const functions = require('firebase-functions');

// We have to import the built version of the server middleware.
const { app } = require('../__sapper__/build/server/server');

app.get('/', (request, response) => {
    response.set(
      'Cache-Control',
      'public, max-age=300, s-maxage=1200, proxy-revalidate'
    );
    response.send(app);
})

exports.ssr = functions
    .region('us-central1')
    .https.onRequest(app);