getInitialProps_solution2.js

const PageWrapper = Comp => (
  class extends React.Component {
    static async getInitialProps(args) {
      return {
        ua: args.req ? args.req.headers['user-agent'] : navigator.userAgent,
        lang args.req.query.language,
        foo: 'bar',
        /* and so on.. */
        ...(Comp.getInitialProps ? await Comp.getInitialProps(args) : null),
      }
    }

    render() {
      return (
        <Comp {...props} />
      )
    }
  }
)