Custom SSR error handling in extension.js causing dev server to fail

[omnichronous]

So I’m trying to customize the error pages in SSR mode. I have a custom route set up to show a 500 error page and I’m following the instructions from the Quasar docs and editing /src-ssr/extension.js in order to see my changes in dev mode. I’m basically testing with code copied from /src-ssr/index.js and my file looks rougly like this:

module.exports.extendApp = function ({ app, ssr }) {
  app.get('*', (req, res) => {
    res.setHeader('Content-Type', 'text/html')
    ssr.renderToString({ req, res }, (err, html) => {
      res.redirect('/error500')
    })
  })
}

With this code, when I try to access any route on the app I get a dev server error. Anything executed in the ssr.renderToString() callback throws the error handleError is not defined in client/node_modules/@quasar/app/lib/dev-server.js.

Alternatively, trying to execute res.redirect('/error500') in the app.get() callback leads to a redirect loop.

So how would redirecting to a custom route work in dev mode?