Change the case of labels | Mapbox GL JS

Use the upcase and downcase expressions to change the case of labels.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Change the case of labels</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no">
<link href="https://api.mapbox.com/mapbox-gl-js/v2.14.1/mapbox-gl.css" rel="stylesheet">
<script src="https://api.mapbox.com/mapbox-gl-js/v2.14.1/mapbox-gl.js"></script>
<style>
body { margin: 0; padding: 0; }
#map { position: absolute; top: 0; bottom: 0; width: 100%; }
</style>
</head>
<body>
<div id="map"></div>
<script>
	// TO MAKE THE MAP APPEAR YOU MUST
	// ADD YOUR ACCESS TOKEN FROM
	// https://account.mapbox.com
	mapboxgl.accessToken = 'YOUR_MAPBOX_ACCESS_TOKEN';
const map = new mapboxgl.Map({
container: 'map', // container ID
// Choose from Mapbox's core styles, or make your own style with Mapbox Studio
style: 'mapbox://styles/mapbox/outdoors-v12', // style URL
center: [-116.231, 43.604], // starting position [lng, lat]
zoom: 11 // starting zoom
});
 
map.on('load', () => {
// data from opendata.cityofboise.org/
map.addSource('off-leash-areas', {
'type': 'geojson',
'data': 'https://docs.mapbox.com/mapbox-gl-js/assets/boise.geojson'
});
map.addLayer({
'id': 'off-leash-areas',
'type': 'symbol',
'source': 'off-leash-areas',
'layout': {
'text-field': [
'format',
['upcase', ['get', 'FacilityName']],
{ 'font-scale': 0.8 },
'\n',
{},
['downcase', ['get', 'Comments']],
{ 'font-scale': 0.6 }
],
'text-font': ['Open Sans Semibold', 'Arial Unicode MS Bold']
}
});
});
</script>
 
</body>
</html>