Use a fallback image
Use a coalesce
expression to display another image when a requested image is not available.
<!DOCTYPE html><html><head><meta charset="utf-8" /><title>Use a fallback image</title><meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" /><script src="https://cdn.jsdelivr.net/npm/@goongmaps/goong-js@1.0.9/dist/goong-js.js"></script><link href="https://cdn.jsdelivr.net/npm/@goongmaps/goong-js@1.0.9/dist/goong-js.css" rel="stylesheet" /><style> body { margin: 0; padding: 0; } #map { position: absolute; top: 0; bottom: 0; width: 100%; }</style></head><body><div id="map"></div><script>goongjs.accessToken = '8qzxZAuxcsctSlmOszInchP1A5GrmRBHJwCBCjO6';var map = new goongjs.Map({container: 'map',style: 'https://tiles.goong.io/assets/goong_map_web.json',center: [-77, 38.75],zoom: 5});map.on('load', function () {map.addSource('points', {'type': 'geojson','data': {'type': 'FeatureCollection','features': [{'type': 'Feature','geometry': {'type': 'Point','coordinates': [-77.03238901390978, 38.913188059745586]},'properties': {'title': 'Washington DC','icon': 'monument'}},{'type': 'Feature','geometry': {'type': 'Point','coordinates': [-79.9959, 40.4406]},'properties': {'title': 'Pittsburgh','icon': 'golf'}},{'type': 'Feature','geometry': {'type': 'Point','coordinates': [-76.2859, 36.8508]},'properties': {'title': 'Norfolk','icon': 'harbor'}}]}});map.addLayer({'id': 'points','type': 'symbol','source': 'points','layout': {'icon-image': ['coalesce',['image', ['concat', ['get', 'icon'], '-15']],['image', 'marker_15']],'text-field': ['get', 'title'],'text-font': ['Roboto Regular'],'text-offset': [0, 0.6],'text-anchor': 'top'}});});</script> </body></html>