leaflet.marker.App.js

import { useEffect, useRef } from 'react';
import L from 'leaflet';
import 'leaflet/dist/leaflet.css';
import markerIconPng from 'leaflet/dist/images/marker-icon.png';
import markShadowPng from 'leaflet/dist/images/marker-shadow.png';

function App() {
  const savedMap = useRef();
  const mapId = 'map';

  useEffect(() => {
    if (savedMap.current) {
      savedMap.current.off();
      savedMap.current.remove();
    }

    const map = L.map(mapId, {
      center: [37.774929, -122.419418],
      zoom: 12,
    });
    savedMap.current = map;

    L.tileLayer('https://tile.openstreetmap.org/{z}/{x}/{y}{r}.png', {
      attribution:
        '&copy; <a href="http://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors',
    }).addTo(map);

    const customIcon = L.icon({
      iconUrl: markerIconPng,
      shadowUrl: markShadowPng,
    });

    L.marker([37.774929, -122.419418], {
      icon: customIcon,
      title: 'My City',
      draggable: true,
    }).addTo(map);
  }, []);

  return <div id={mapId}></div>;
}

export default App;