React Router protected routes

Hi, folks. I’ve been trying to implement protected routes in React Router, and I’m right on the edge of having it figured out, but I’ve gotten stuck on the last step and I was hoping someone else might see the way forward.
I’ve built a higher order component to reroute the user if they’re not authenticated and render the desired route if they are, but I can’t for the life of me figure out how to get that information for use in my component.

const ProtectedRoute = ({ component: Component, }) => {
  return (
      render={props => {
        if (!AUTHENTICATED) {
          return <Redirect to="/login" />;
        return <Component {...props} />;

The if (!AUTHENTICATED) part is where I’m stuck.
I’m using Passport, and have all the authentication stuff worked out on my Express server, so all I have to do is make a fetch request to see if the user is authenticated, but I can’t make that request in the return statement of the ProtectedRoute component. I tried adding a function before the return statement to fetch the user’s authentication status, but couldn’t figure that out either. If I use async at any point, the whole thing seems to fall apart, and I can’t get the info from the server without using async. It’s been hours, and my brain is falling out, so any input would be very very helpful.
Thanks for your time!