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Filter symbols by text input

Filter symbols by icon name by typing in a text input.

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Filter symbols by text input</title>
    <meta property="og:description" content="Filter symbols by icon name by typing in a text input." />
    <meta charset='utf-8'>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel='stylesheet' href='https://unpkg.com/[email protected]/dist/maplibre-gl.css' />
    <script src='https://unpkg.com/[email protected]/dist/maplibre-gl.js'></script>
    <style>
        body { margin: 0; padding: 0; }
        html, body, #map { height: 100%; }
    </style>
</head>
<body>
<style>
    .filter-ctrl {
        position: absolute;
        top: 10px;
        right: 10px;
        z-index: 1;
    }

    .filter-ctrl input[type='text'] {
        font: 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;
        width: 100%;
        border: 0;
        background-color: #fff;
        margin: 0;
        color: rgba(0, 0, 0, 0.5);
        padding: 10px;
        box-shadow: 0 0 0 2px rgba(0, 0, 0, 0.1);
        border-radius: 3px;
        width: 180px;
    }
</style>
<div id="map"></div>
<div class="filter-ctrl">
    <input
        id="filter-input"
        type="text"
        name="filter"
        placeholder="Filter by name"
    />
</div>

<script>
    const places = {
        'type': 'FeatureCollection',
        'features': [
            {
                'type': 'Feature',
                'properties': {
                    'icon': 'theatre'
                },
                'geometry': {
                    'type': 'Point',
                    'coordinates': [-77.038659, 38.931567]
                }
            },
            {
                'type': 'Feature',
                'properties': {
                    'icon': 'theatre'
                },
                'geometry': {
                    'type': 'Point',
                    'coordinates': [-77.003168, 38.894651]
                }
            },
            {
                'type': 'Feature',
                'properties': {
                    'icon': 'bar'
                },
                'geometry': {
                    'type': 'Point',
                    'coordinates': [-77.090372, 38.881189]
                }
            },
            {
                'type': 'Feature',
                'properties': {
                    'icon': 'bicycle'
                },
                'geometry': {
                    'type': 'Point',
                    'coordinates': [-77.052477, 38.943951]
                }
            },
            {
                'type': 'Feature',
                'properties': {
                    'icon': 'music'
                },
                'geometry': {
                    'type': 'Point',
                    'coordinates': [-77.031706, 38.914581]
                }
            },
            {
                'type': 'Feature',
                'properties': {
                    'icon': 'music'
                },
                'geometry': {
                    'type': 'Point',
                    'coordinates': [-77.020945, 38.878241]
                }
            },
            {
                'type': 'Feature',
                'properties': {
                    'icon': 'music'
                },
                'geometry': {
                    'type': 'Point',
                    'coordinates': [-77.007481, 38.876516]
                }
            }
        ]
    };

    const layerIDs = []; // Will contain a list used to filter against.
    const filterInput = document.getElementById('filter-input');
    const map = new maplibregl.Map({
        container: 'map',
        style:
            'https://api.maptiler.com/maps/streets/style.json?key=get_your_own_OpIi9ZULNHzrESv6T2vL',
        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 layerID = `poi-${symbol}`;

            // 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': `${symbol}_15`,
                        'icon-overlap': 'always',
                        'text-field': symbol,
                        'text-font': [
                            'Open Sans Bold',
                            'Arial Unicode MS Bold'
                        ],
                        'text-size': 11,
                        'text-transform': 'uppercase',
                        'text-letter-spacing': 0.05,
                        'text-offset': [0, 1.5]
                    },
                    'paint': {
                        'text-color': '#202',
                        'text-halo-color': '#fff',
                        'text-halo-width': 2
                    },
                    'filter': ['==', 'icon', symbol]
                });

                layerIDs.push(layerID);
            }
        });

        filterInput.addEventListener('keyup', (e) => {
            // If the input value matches a layerID set
            // it's visibility to 'visible' or else hide it.
            const value = e.target.value.trim().toLowerCase();
            layerIDs.forEach((layerID) => {
                map.setLayoutProperty(
                    layerID,
                    'visibility',
                    layerID.indexOf(value) > -1 ? 'visible' : 'none'
                );
            });
        });
    });
</script>
</body>
</html>