Change building color based on zoom level | TrackAsia GL JS Docs

Use the interpolate expression to ease-in the building layer and smoothly fade from one color to the next.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Change building color based on zoom level</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src="https://unpkg.com/trackasia-gl@1.0.5/dist/trackasia-gl.js"></script>
<link href="https://unpkg.com/trackasia-gl@1.0.5/dist/trackasia-gl.css" rel="stylesheet" />
<style>
	body { margin: 0; padding: 0; }
	#map { position: absolute; top: 0; bottom: 0; width: 100%; }
</style>
</head>
<body>
<style>
#zoom {
display: block;
position: relative;
margin: 20px auto;
width: 50%;
height: 40px;
padding: 10px;
border: none;
border-radius: 3px;
font-size: 12px;
text-align: center;
color: #fff;
background: #ee8a65;
}
</style>
<div id="map"></div>
<button id="zoom">Zoom to buildings</button>
<script>
var map = new trackasiagl.Map({
container: 'map',
style: 'https://maps.track-asia.com/styles/v1/streets.json?key=public_key',
center: {"lat":10.762622,"lng":106.660172},
zoom: 11
});
 
map.on('load', function () {
map.setPaintProperty('building', 'fill-color', [
'interpolate',
['exponential', 0.5],
['zoom'],
15,
'#e2714b',
22,
'#eee695'
]);
 
map.setPaintProperty('building', 'fill-opacity', [
'interpolate',
['exponential', 0.5],
['zoom'],
15,
0,
22,
1
]);
});
 
document.getElementById('zoom').addEventListener('click', function () {
map.zoomTo(18, { duration: 9000 });
});
</script>
 
</body>
</html>