Filter symbols by toggling a list | NMaps GL JS Docs

Filter a set of symbols based on a property value in the data.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Filter symbols by toggling a list</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src="https://cdn.ndrive.com/nmapsgl/v.1.6.8/nmaps-gl.js"></script>
<link href="https://cdn.ndrive.com/nmapsgl/v.1.6.8/nmaps-gl.css" rel="stylesheet" />
<style>
	body { margin: 0; padding: 0; }
	#map { position: absolute; top: 0; bottom: 0; width: 100%; }
</style>
</head>
<body>
<style>
.filter-group {
font: 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;
font-weight: 600;
position: absolute;
top: 10px;
right: 10px;
z-index: 1;
border-radius: 3px;
width: 120px;
color: #fff;
}
 
.filter-group input[type='checkbox']:first-child + label {
border-radius: 3px 3px 0 0;
}
 
.filter-group label:last-child {
border-radius: 0 0 3px 3px;
border: none;
}
 
.filter-group input[type='checkbox'] {
display: none;
}
 
.filter-group input[type='checkbox'] + label {
background-color: #3386c0;
display: block;
cursor: pointer;
padding: 10px;
border-bottom: 1px solid rgba(0, 0, 0, 0.25);
}
 
.filter-group input[type='checkbox'] + label {
background-color: #3386c0;
text-transform: capitalize;
}
 
.filter-group input[type='checkbox'] + label:hover,
.filter-group input[type='checkbox']:checked + label {
background-color: #4ea0da;
}
 
.filter-group input[type='checkbox']:checked + label:before {
content: '✔';
margin-right: 5px;
}
</style>
<div id="map"></div>
<nav id="filter-group" class="filter-group"></nav>
 
<script>
	// TO MAKE THE MAP APPEAR YOU MUST ADD YOUR ACCESS TOKEN
	nmapsgl.accessToken = '<your access token here>';
	
const places = {
'type': 'FeatureCollection',
'features': [
{
'type': 'Feature',
'properties': {
'icon': 'T174',
'text': 'Theatre'
},
'geometry': {
'type': 'Point',
'coordinates': [-77.038659, 38.931567]
}
},
{
'type': 'Feature',
'properties': {
'icon': 'T174',
'text': 'Theatre'
},
'geometry': {
'type': 'Point',
'coordinates': [-77.003168, 38.894651]
}
},
{
'type': 'Feature',
'properties': {
'icon': 'T166',
'text': 'Bar'
},
'geometry': {
'type': 'Point',
'coordinates': [-77.090372, 38.881189]
}
},
{
'type': 'Feature',
'properties': {
'icon': 'T202',
'text': 'Metro'
},
'geometry': {
'type': 'Point',
'coordinates': [-77.052477, 38.943951]
}
},
{
'type': 'Feature',
'properties': {
'icon': 'T159',
'text': 'Cinema'
},
'geometry': {
'type': 'Point',
'coordinates': [-77.031706, 38.914581]
}
},
{
'type': 'Feature',
'properties': {
'icon': 'T159',
'text': 'Cinema'
},
'geometry': {
'type': 'Point',
'coordinates': [-77.020945, 38.878241]
}
},
{
'type': 'Feature',
'properties': {
'icon': 'T174',
'text': 'Cinema'
},
'geometry': {
'type': 'Point',
'coordinates': [-77.007481, 38.876516]
}
}
]
};
 
const filterGroup = document.getElementById('filter-group');
const map = new nmapsgl.Map({
container: 'map',
style: 'Streets',
center: [-77.04, 38.907],
zoom: 11.15
});
 
map.on('load', () => {
// Add a GeoJSON source containing place coordinates and information.
map.addSource('places', {
'type': 'geojson',
'data': places
});
 
places.features.forEach((feature) => {
const symbol = feature.properties['icon'];
const text = feature.properties['text'];
const layerID = 'poi-' + text.toLowerCase();
 
// Add a layer for this symbol type if it hasn't been added already.
if (!map.getLayer(layerID)) {
map.addLayer({
'id': layerID,
'type': 'symbol',
'source': 'places',
'layout': {
'icon-image': 'poi-category-' + symbol,
'icon-allow-overlap': true
},
'filter': ['==', 'icon', symbol]
});
 
// Add checkbox and label elements for the layer.
const input = document.createElement('input');
input.type = 'checkbox';
input.id = layerID;
input.checked = true;
filterGroup.appendChild(input);
 
const label = document.createElement('label');
label.setAttribute('for', layerID);
label.textContent = text;
filterGroup.appendChild(label);
 
// When the checkbox changes, update the visibility of the layer.
input.addEventListener('change', (e) => {
map.setLayoutProperty(
layerID,
'visibility',
e.target.checked ? 'visible' : 'none'
);
});
}
});
});
</script>
 
</body>
</html>