MapboxGL threshold style slider by wboykinm

index.html

<!DOCTYPE html>
<html>
<head>
    <meta charset='utf-8' />
    <title>Adjust a layer</title>
    <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />
    <script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.45.0/mapbox-gl.js'></script>
    <link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.45.0/mapbox-gl.css' rel='stylesheet' />
    <style>
        body { margin:0; padding:0; }
        #map { position:absolute; top:0; bottom:0; width:100%; }
    </style>
</head>
<body>

<style>
.map-overlay {
    font:bold 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;
    position: absolute;
    width: 25%;
    top: 0;
    left: 0;
    padding: 10px;
}

.map-overlay .map-overlay-inner {
    background-color: #fff;
    box-shadow:0 1px 2px rgba(0, 0, 0, 0.20);
    border-radius: 3px;
    padding: 10px;
    margin-bottom: 10px;
}

.map-overlay label {
    display: block;
    margin: 0 0 10px;
}

.map-overlay input {
    background-color: transparent;
    display: inline-block;
    width: 100%;
    position: relative;
    margin: 0;
    cursor: ew-resize;
}
</style>

<div id='map'></div>

<div class='map-overlay top'>
    <div class='map-overlay-inner'>
        <label>Score threshold: <span id='slider-value'>0.75</span></label>
        <input id='slider' type='range' min='0' max='1' step='0.05' value='0.75' />
    </div>
</div>

<script>
mapboxgl.accessToken = 'pk.eyJ1IjoiZmFyYWRheTIiLCJhIjoiTUVHbDl5OCJ9.buFaqIdaIM3iXr1BOYKpsQ';
var map = new mapboxgl.Map({
    container: 'map',
    style: 'mapbox://styles/faraday2/cjidg4nxa1c102spa1p0gy662',
    center: [-87.6321, 41.8362],
    minZoom: 5,
    maxZoom: 13,
    zoom: 9.5
});

var slider = document.getElementById('slider');
var sliderValue = document.getElementById('slider-value');
  
map.addControl(new mapboxgl.NavigationControl());

map.on('load', function() {
		map.addLayer({
        'id': 'scores',
        'type': 'circle',
        'source': {
          'type': 'geojson',
          'data': 'https://rawgit.com/wboykinm/be013c300ee9a6e0cea2897a9de56fb3/raw/72319ef9a549634360cc6b6186fc81357fe8385f/chicago.geojson'
        },
        'paint': {
            'circle-radius': [
                'step',
                ['get', 'value'],
                6, 0.7,
                16
            ],
            'circle-color': [
                'step',
                ['get', 'value'],
                '#fff', 0.7,
                '#B26BFB'
            ]
        }
    });

    slider.addEventListener('input', function(e) {
        map.setPaintProperty('scores', 'circle-color', [ 'step', ['get', 'value'], '#fff', parseFloat(e.target.value, 1), '#B26BFB' ]);
        map.setPaintProperty('scores', 'circle-radius', [ 'step', ['get', 'value'], 6, parseFloat(e.target.value, 1), 16 ]);
        sliderValue.textContent = e.target.value;
    });
});
</script>

</body>
</html>