The map load event NOT works

by Koji NAKAMURA

HTML

<link rel="stylesheet" href="https://unpkg.com/[email protected]/dist/leaflet.css" />
<script src="https://unpkg.com/[email protected]/dist/leaflet.js"></script>
<div id="map" style="width: 600px; height: 400px"></div>
<script>
  var map = L.map('map').setView([51.505, -0.09], 13);
  L.tileLayer('https://api.mapbox.com/styles/v1/k-nakamura/ciujeilwt003u2jqn47v2ozcs/tiles/256/{z}/{x}/{y}?access_token=pk.eyJ1Ijoiay1uYWthbXVyYSIsImEiOiJjaXVqZWd6OTMwMGhjMnlxaXZrcGhzczJtIn0.LQwDcl6aZFQRx8dPfneFHQ', {
    attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, <a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, Imagery © <a href="http://mapbox.com">Mapbox</a>',
    maxZoom: 18
  }).addTo(map);

  map.on('load', function() {
    alert('The map load event is fired');
  });

</script>