Add static text labels to the center of features. This is not the same as fitting labels dynamically. The labels will collide as you zoom out.
<html>
<head>
<meta charset="utf-8" />
<title>Add static text labels</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>
<!-- Load Esri Leaflet from CDN -->
<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>
<script>
</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>
<style>
.label {
font-weight: 700;
text-transform: uppercase;
text-align: center;
margin-top: -1em;
}
.label div {
position: relative;
left: -50%;
top: 10px;
text-shadow: 0px 2px 1px rgba(255, 255, 255, 0.85);
}
</style>
<div id="map"></div>
<script>
const apiKey = "YOUR_API_KEY";
const map = L.map("map").setView([37.428, -121.978], 9);
L.esri.Vector.vectorBasemapLayer("arcgis/oceans/base", {
apikey: apiKey
}).addTo(map);
const earthquakes = L.esri
.featureLayer({
url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Earthquakes_Since1970/MapServer/0"
})
.addTo(map);
const labels = {};
earthquakes.on("createfeature", function (e) {
const id = e.feature.id;
const feature = earthquakes.getFeature(id);
const center = feature.getLatLng();
const label = L.marker(center, {
icon: L.divIcon({
iconSize: null,
className: "label",
html: "<div>" + e.feature.properties.name + "</div>"
})
}).addTo(map);
labels[id] = label;
});
earthquakes.on("addfeature", function (e) {
const label = labels[e.feature.id];
if (label) {
label.addTo(map);
}
});
earthquakes.on("removefeature", function (e) {
const label = labels[e.feature.id];
if (label) {
map.removeLayer(label);
}
});
</script>
</body>
</html>