Show polygon information on click

When a user clicks a polygon, show a Popup containing more information. See the example: https://docs.mapbox.com//mapbox-gl-js/example/polygon-popup-on-click/

by fxi

HTML

<script src="https://api.mapbox.com/mapbox-gl-js/v1.10.1/mapbox-gl.js"></script>
<link rel="stylesheet" href="https://api.mapbox.com/mapbox-gl-js/v1.10.1/mapbox-gl.css">


<div id="map"></div>

CSS

body { margin: 0; padding: 0; }
	#map { position: absolute; top: 0; bottom: 0; width: 100%; }

    .mapboxgl-popup {
        max-width: 400px;
        font: 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;
    }

JavaScript

const gj = fetch('https://gist.githubusercontent.com/fxi/93c7f41cc0e18674a967b8758a173b44/raw/809f4701a687bbd00f31a2f52631c15a23585230/map.geojson')


	mapboxgl.accessToken = 'pk.eyJ1IjoiaGVsc2lua2kiLCJhIjoiY2puZW5rZ3N6MGRzYzNwb3drOW12MWEzdyJ9.IZC03hW3hKtBcbMgD0_KPw';
    var map = new mapboxgl.Map({
        container: 'map',
        style: 'mapbox://styles/mapbox/streets-v11',
        center: [-100.04, 38.907],
        zoom: 3
    });

    map.on('load', function() {
        // Add a source for the state polygons.
        map.addSource('bathymetry', {
            'type': 'vector',
            'url': 'mapbox://helsinki.58vx3k2v'
                'https://d2ad6b4ur7yvpq.cloudfront.net/naturalearth-3.3.0/ne_110m_admin_1_states_provinces_shp.geojson'
        });

        // Add a layer showing the state polygons.
        map.addLayer({
            'id': 'states-layer',
            'type': 'fill',
            'source': 'states',
            'paint': {
                'fill-color': 'rgba(200, 100, 240, 0.4)',
                'fill-outline-color': 'rgba(200, 100, 240, 1)'
            }
        });

        // When a click event occurs on a feature in the states layer, open a popup at the
        // location of the click, with description HTML from its properties.
        map.on('click', 'states-layer', function(e) {
            new mapboxgl.Popup()
                .setLngLat(e.lngLat)
                .setHTML(e.features[0].properties.name)
                .addTo(map);
        });

        // Change the cursor to a pointer when the mouse is over the states layer.
        map.on('mouseenter', 'states-layer', function() {
            map.getCanvas().style.cursor = 'pointer';
        });

        // Change it back to a pointer when it leaves.
        map.on('mouseleave', 'states-layer', function() {
            map.getCanvas().style.cursor = '';
        });
    });