_app.js

// ...

// move our routes array out of component
const routes = [
  {
    path: '/',
    asyncComponent: () => import('./index'),
  },
  // add dynamic Framework7 route to ./blog/[postID].js page
  {
    path: '/blog/:postID',
    asyncComponent: () => import('./blog/[postID]'),
  }
]

function MyApp({ Component, pageProps }) {
  // ...
  return (
    <App url={url} routes={routes}>
      {/* ... */}
    </App>
  );
}

export default MyApp