MapExample.js

import React, { useEffect } from "react";
import { Map, GeoJSON, TileLayer } from "react-leaflet";
import leafletStream from "leaflet-geojson-stream";

function StreamGeoJsonLayer(props) {
  const layerRef = React.useRef();
  const { url } = props;
  useEffect(() => {
    const gj = layerRef.current.leafletElement;
    leafletStream.ajax(url, gj).on("end", function () {
      console.log("all done!");
    });
  }, []);

  return <GeoJSON ref={layerRef} />;
}

function MapExample(props) {
  return (
    <Map center={props.center} zoom={props.zoom}>
      <TileLayer
        url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
        attribution='&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
      />
      <StreamGeoJsonLayer url={"http://localhost:8000/data"} />
    </Map>
  );
}

export default MapExample;