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/v3.3.0/mapbox-gl.css" rel="stylesheet">
<script src="https://api.mapbox.com/mapbox-gl-js/v3.3.0/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>
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