develop/leaflet/query_with_html5_location_turf/index.html

<!DOCTYPE html>
<html>
<head>
  <meta charset=utf-8 />
  <title>Esri Leaflet and Turf</title>
  <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />

  <!-- Load Leaflet from CDN-->
  <link rel="stylesheet" href="https://unpkg.com/leaflet@1.0.1/dist/leaflet.css" />
  <script src="https://unpkg.com/leaflet@1.0.1/dist/leaflet-src.js"></script>

  <!-- Load Esri Leaflet from CDN -->
  <script src="https://unpkg.com/esri-leaflet@2.0.4"></script>

  <!-- Load turf -->
  <script src="https://api.tiles.mapbox.com/mapbox.js/plugins/turf/v2.0.0/turf.min.js"></script>

  <style>
    body { margin:0; padding:0; }
    #mapDiv { position: absolute; top:0; bottom:0; right:0; left:0; }
  </style>
</head>
<body>

<div id="mapDiv"></div>

<script>
  // html5 geolocation requires a secure connection
  if (window.location.hostname != 'localhost' && window.location.protocol != "https:") {
    window.location.protocol = "https";
  }

  var map = L.map('mapDiv');
  map.setView([34, -118], 10);

  // create a variable to represent the location of the end user
  var userLocation;

  L.esri.basemapLayer('DarkGray').addTo(map);

  // ask leaflet to use HTML5 to query the user location
  map.locate({
    setView: true
  });

  // listen for the result of that asynchronous method
  map.on('locationfound', function(evt) {
    // construct the GeoJSON once we know where they are
    userLocation = turf.point([evt.latlng.lng, evt.latlng.lat]);

    // now lets see what census block the user is inside of
    var censusBlocks = L.esri.featureLayer({
      url: 'https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/1',
      style: wereStylin
    }).addTo(map);
  });

  function wereStylin (feature) {
    // only show the census block the user is inside of
    if (userLocation && turf.inside(userLocation, feature) ) {
      return {
        fillOpacity: 0.2,
        opacity: 0.5
      }
    }
    else {
      return {
        fillOpacity: 0,
        opacity: 0
      }
    }
  }
</script>
</body>
</html>