// app/server.js
import { Store } from 'svelte/store.js';
// ...

app.use(sapper({
  routes,
  store: req => {
    return new Store({
      user: req.session.passport && req.session.passport.user
    });
  }
}));

// app/client
import { init } from 'sapper/runtime.js';
import { Store } from 'svelte/store.js';
import { routes } from './manifest/client.js';

init(target, routes, {
  store: data => new Store(data)
});