base-ui.js

init(lat, lng) {
    let mapEl = document.createElement('div');
    mapEl.id = 'map';
    document.body.appendChild(mapEl);

    // http://leafletjs.com/reference-1.3.0.html#map
    let map = (this.map = leaflet.map(mapEl, this.options));
    leaflet.tileLayer(tileUrl, { attribution }).addTo(map);
    map.setView([lat, lng], defaultZoomLevel);

    // http://leafletjs.com/reference-1.3.0.html#map-event
    let onMapChange = () => this.emit('update', map.getBounds());
    map.on('viewreset', onMapChange);
    map.on('moveend', onMapChange);

    // Show a marker at our current location
    this.currentLocationMarker = leaflet
      .marker([lat, lng], {
        title: 'Current Location',
        icon: svgMarker.location
      })
      .addTo(map);

    log.info(`Map initialized with centre lat=${lat}, lng=${lng}`);
  }