fetch.js

class App extends React.Component {
  static async getInitialProps({ req, query, asPath, pathname }) {
    
    let baseUrl = req ? `${req.protocol}://${req.get("Host")}` : "";
    
    let data = await fetch(baseUrl + 'relativeURL')
   
    
    return {
      data: data
      
    }
    
  }