Change the case of labels

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' />
    <script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.51.0/mapbox-gl.js'></script>
    <link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.51.0/mapbox-gl.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>
mapboxgl.accessToken = '<your access token here>';

var map = new mapboxgl.Map({
    container: 'map', // container id
    style: 'mapbox://styles/mapbox/streets-v10', // stylesheet location
    center: [-116.231, 43.604], // starting position [lng, lat]
    zoom: 11 // starting zoom
});

map.on('load', function() {
    map.addLayer({
        'id': 'off-leash-areas',
        'type': 'symbol',
        // data from opendata.cityofboise.org/
        'source': {
            'type': 'geojson',
            'data': 'https://www.mapbox.com/mapbox-gl-js/assets/boise.geojson'

        },
        "layout": {
            "icon-image": 'dog-park-11',
            "text-field": ['format',
                ['upcase', ['get', 'FacilityName']], { 'font-scale': .8 },
                '\n', {},
                ['downcase', ['get', 'Comments']], { 'font-scale': .6 }],
            "text-font": ["Open Sans Semibold", "Arial Unicode MS Bold"],
            "text-offset": [0, 0.6],
            "text-anchor": "top"
        }
    });

});
</script>
</div>

</body>
</html>
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