You can convert ArcGIS features to GeoJSON using the arcgis method.
<html>
<head>
<meta charset="utf-8" />
<title>Convert ArcGIS features to GeoJSON</title>
<meta name="viewport" content="initial-scale=1, maximum-scale=1, user-scalable=no" />
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.9.4/dist/leaflet.css" crossorigin="" />
<script src="https://unpkg.com/leaflet@1.9.4/dist/leaflet.js" crossorigin=""></script>
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<script src="https://unpkg.com/esri-leaflet@3.0.12/dist/esri-leaflet.js"></script>
<!-- Load Esri Leaflet Vector from CDN -->
<script src="https://unpkg.com/esri-leaflet-vector@4.2.3/dist/esri-leaflet-vector.js" crossorigin=""></script>
<style>
html,
body,
#map {
padding: 0;
margin: 0;
height: 100%;
width: 100%;
font-family: Arial, Helvetica, sans-serif;
font-size: 14px;
color: #323232;
}
</style>
</head>
<body>
<div id="map"></div>
<script>
const apiKey = "YOUR_API_KEY";
const map = L.map("map");
L.esri.Vector.vectorBasemapLayer("osm/streets-relief", {
apikey: apiKey
}).addTo(map);
L.esri.get("https://www.arcgis.com/sharing/content/items/62914b2820c24d4e95710ebae77937cb/data", {}, function (error, response) {
if (error) {
return;
}
const arcGISFeatures = response.operationalLayers[0].featureCollection.layers[0].featureSet.features;
const idField = response.operationalLayers[0].featureCollection.layers[0].layerDefinition.objectIdField;
// empty geojson feature collection
const geoJSONFeatureCollection = {
type: "FeatureCollection",
features: []
};
for (let i = arcGISFeatures.length - 1; i >= 0; i--) {
// convert ArcGIS Feature to GeoJSON Feature
const geoJSONFeature = L.esri.Util.arcgisToGeoJSON(arcGISFeatures[i], idField);
// unproject the web mercator coordinates to lat/lng
const latlng = L.Projection.Mercator.unproject(L.point(geoJSONFeature.geometry.coordinates));
geoJSONFeature.geometry.coordinates = [latlng.lng, latlng.lat];
geoJSONFeatureCollection.features.push(geoJSONFeature);
}
const geojsonLayer = L.geoJSON(geoJSONFeatureCollection).addTo(map);
map.fitBounds(geojsonLayer.getBounds());
});
</script>
</body>
</html>