coalesce

by Tristen Brown

HTML

<link rel="stylesheet" href="https://api.tiles.mapbox.com/mapbox-gl-js/v1.12.0/mapbox-gl.css">
<script src="https://api.tiles.mapbox.com/mapbox-gl-js/v1.12.0/mapbox-gl.js"></script>
<div id="map"></div>

CSS

body {
    margin: 0;
    padding: 0;
  }

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

JavaScript

mapboxgl.accessToken = 'pk.eyJ1IjoidHJpc3RlbiIsImEiOiJjajZoOXU4Z2kwNnppMnlxd2d6bTFvZ2xtIn0.PP7AoUakMfeqdXFHdsY0oA';

const style = {
  version: 8,
  center: [140.922272, 37.71389],
  zoom: 16,
  sources: {
    composite: {
      url: 'mapbox://mapbox.mapbox-streets-v8',
      type: 'vector'
    }
  },
  sprite: 'mapbox://sprites/mapbox/streets-v11',
  glyphs: 'mapbox://fonts/tristen/{fontstack}/{range}.pbf',
  layers: [{
      id: 'land',
      type: 'background',
      paint: {
        'background-color': 'hsl(35, 32%, 91%)'
      }
    },
    {
      id: 'water',
      type: 'fill',
      source: 'composite',
      'source-layer': 'water',
      paint: {
        'fill-color': 'hsl(196, 80%, 70%)'
      }
    },
    {
      id: 'poi',
      type: 'symbol',
      source: 'composite',
      'source-layer': 'poi_label',
      layout: {
        'icon-image': [
          'case',
          ['has', 'maki_beta'],
          [
            'coalesce',
            ['image', ['concat', ['get', 'maki_beta'], '-15']],
            ['image', ['concat', ['get', 'maki'], '-15']]
          ],
          ['image', ['concat', ['get', 'maki'], '-15']]
        ]
      }
    }
  ]
};

const map = new mapboxgl.Map({
  container: 'map',
  style
});