L.Control.Locate.js

/*!
Copyright (c) 2016 Dominik Moritz

This file is part of the leaflet locate control. It is licensed under the MIT license.
You can find the project at: https://github.com/domoritz/leaflet-locatecontrol
*/
(function (factory, window) {
  // see https://github.com/Leaflet/Leaflet/blob/master/PLUGIN-GUIDE.md#module-loaders
  // for details on how to structure a leaflet plugin.

  // define an AMD module that relies on 'leaflet'
  if (typeof define === "function" && define.amd) {
    define(["leaflet"], factory);

    // define a Common JS module that relies on 'leaflet'
  } else if (typeof exports === "object") {
    if (typeof window !== "undefined" && window.L) {
      module.exports = factory(L);
    } else {
      module.exports = factory(require("leaflet"));
    }
  }

  // attach your plugin to the global 'L' variable
  if (typeof window !== "undefined" && window.L) {
    window.L.Control.Locate = factory(L);
  }
})(function (L) {
  const LDomUtilApplyClassesMethod = (method, element, classNames) => {
    classNames = classNames.split(" ");
    classNames.forEach(function (className) {
      L.DomUtil[method].call(this, element, className);
    });
  };

  const addClasses = (el, names) => LDomUtilApplyClassesMethod("addClass", el, names);
  const removeClasses = (el, names) => LDomUtilApplyClassesMethod("removeClass", el, names);

  /**
   * Compatible with L.Circle but a true marker instead of a path
   */
  const LocationMarker = L.Marker.extend({
    initialize(latlng, options) {
      L.Util.setOptions(this, options);
      this._latlng = latlng;
      this.createIcon();
    },

    /**
     * Create a styled circle location marker
     */
    createIcon() {
      const opt = this.options;

      let style = "";

      if (opt.color !== undefined) {
        style += `stroke:${opt.color};`;
      }
      if (opt.weight !== undefined) {
        style += `stroke-width:${opt.weight};`;
      }
      if (opt.fillColor !== undefined) {
        style += `fill:${opt.fillColor};`;
      }
      if (opt.fillOpacity !== undefined) {
        style += `fill-opacity:${opt.fillOpacity};`;
      }
      if (opt.opacity !== undefined) {
        style += `opacity:${opt.opacity};`;
      }

      const icon = this._getIconSVG(opt, style);

      this._locationIcon = L.divIcon({
        className: icon.className,
        html: icon.svg,
        iconSize: [icon.w, icon.h]
      });

      this.setIcon(this._locationIcon);
    },

    /**
     * Return the raw svg for the shape
     *
     * Split so can be easily overridden
     */
    _getIconSVG(options, style) {
      const r = options.radius;
      const w = options.weight;
      const s = r + w;
      const s2 = s * 2;
      const svg =
        `<svg xmlns="http://www.w3.org/2000/svg" width="${s2}" height="${s2}" version="1.1" viewBox="-${s} -${s} ${s2} ${s2}">` +
        '<circle r="' +
        r +
        '" style="' +
        style +
        '" />' +
        "</svg>";
      return {
        className: "leaflet-control-locate-location",
        svg,
        w: s2,
        h: s2
      };
    },

    setStyle(style) {
      L.Util.setOptions(this, style);
      this.createIcon();
    }
  });

  const CompassMarker = LocationMarker.extend({
    initialize(latlng, heading, options) {
      L.Util.setOptions(this, options);
      this._latlng = latlng;
      this._heading = heading;
      this.createIcon();
    },

    setHeading(heading) {
      this._heading = heading;
    },

    /**
     * Create a styled arrow compass marker
     */
    _getIconSVG(options, style) {
      const r = options.radius;
      const w = options.width + options.weight;
      const h = (r + options.depth + options.weight) * 2;
      const path = `M0,0 l${options.width / 2},${options.depth} l-${w},0 z`;
      const svgstyle = `transform: rotate(${this._heading}deg)`;
      const svg =
        `<svg xmlns="http://www.w3.org/2000/svg" width="${w}" height="${h}" version="1.1" viewBox="-${w / 2} 0 ${w} ${h}" style="${svgstyle}">` +
        '<path d="' +
        path +
        '" style="' +
        style +
        '" />' +
        "</svg>";
      return {
        className: "leaflet-control-locate-heading",
        svg,
        w,
        h
      };
    }
  });

  const LocateControl = L.Control.extend({
    options: {
      /** Position of the control */
      position: "topleft",
      /** The layer that the user's location should be drawn on. By default creates a new layer. */
      layer: undefined,
      /**
       * Automatically sets the map view (zoom and pan) to the user's location as it updates.
       * While the map is following the user's location, the control is in the `following` state,
       * which changes the style of the control and the circle marker.
       *
       * Possible values:
       *  - false: never updates the map view when location changes.
       *  - 'once': set the view when the location is first determined
       *  - 'always': always updates the map view when location changes.
       *              The map view follows the user's location.
       *  - 'untilPan': like 'always', except stops updating the
       *                view if the user has manually panned the map.
       *                The map view follows the user's location until she pans.
       *  - 'untilPanOrZoom': (default) like 'always', except stops updating the
       *                view if the user has manually panned the map.
       *                The map view follows the user's location until she pans.
       */
      setView: "untilPanOrZoom",
      /** Keep the current map zoom level when setting the view and only pan. */
      keepCurrentZoomLevel: false,
      /** After activating the plugin by clicking on the icon, zoom to the selected zoom level, even when keepCurrentZoomLevel is true. Set to 'false' to disable this feature. */
      initialZoomLevel: false,
      /**
       * This callback can be used to override the viewport tracking
       * This function should return a LatLngBounds object.
       *
       * For example to extend the viewport to ensure that a particular LatLng is visible:
       *
       * getLocationBounds: function(locationEvent) {
       *    return locationEvent.bounds.extend([-33.873085, 151.219273]);
       * },
       */
      getLocationBounds(locationEvent) {
        return locationEvent.bounds;
      },
      /** Smooth pan and zoom to the location of the marker. Only works in Leaflet 1.0+. */
      flyTo: false,
      /**
       * The user location can be inside and outside the current view when the user clicks on the
       * control that is already active. Both cases can be configures separately.
       * Possible values are:
       *  - 'setView': zoom and pan to the current location
       *  - 'stop': stop locating and remove the location marker
       */
      clickBehavior: {
        /** What should happen if the user clicks on the control while the location is within the current view. */
        inView: "stop",
        /** What should happen if the user clicks on the control while the location is outside the current view. */
        outOfView: "setView",
        /**
         * What should happen if the user clicks on the control while the location is within the current view
         * and we could be following but are not. Defaults to a special value which inherits from 'inView';
         */
        inViewNotFollowing: "inView"
      },
      /**
       * If set, save the map bounds just before centering to the user's
       * location. When control is disabled, set the view back to the
       * bounds that were saved.
       */
      returnToPrevBounds: false,
      /**
       * Keep a cache of the location after the user deactivates the control. If set to false, the user has to wait
       * until the locate API returns a new location before they see where they are again.
       */
      cacheLocation: true,
      /** If set, a circle that shows the location accuracy is drawn. */
      drawCircle: true,
      /** If set, the marker at the users' location is drawn. */
      drawMarker: true,
      /** If set and supported then show the compass heading */
      showCompass: true,
      /** The class to be used to create the marker. For example L.CircleMarker or L.Marker */
      markerClass: LocationMarker,
      /** The class us be used to create the compass bearing arrow */
      compassClass: CompassMarker,
      /** Accuracy circle style properties. NOTE these styles should match the css animations styles */
      circleStyle: {
        className: "leaflet-control-locate-circle",
        color: "#136AEC",
        fillColor: "#136AEC",
        fillOpacity: 0.15,
        weight: 0
      },
      /** Inner marker style properties. Only works if your marker class supports `setStyle`. */
      markerStyle: {
        className: "leaflet-control-locate-marker",
        color: "#fff",
        fillColor: "#2A93EE",
        fillOpacity: 1,
        weight: 3,
        opacity: 1,
        radius: 9
      },
      /** Compass */
      compassStyle: {
        fillColor: "#2A93EE",
        fillOpacity: 1,
        weight: 0,
        color: "#fff",
        opacity: 1,
        radius: 9, // How far is the arrow from the center of the marker
        width: 9, // Width of the arrow
        depth: 6 // Length of the arrow
      },
      /**
       * Changes to accuracy circle and inner marker while following.
       * It is only necessary to provide the properties that should change.
       */
      followCircleStyle: {},
      followMarkerStyle: {
        // color: '#FFA500',
        // fillColor: '#FFB000'
      },
      followCompassStyle: {},
      /** The CSS class for the icon. For example fa-location-arrow or fa-map-marker */
      icon: "leaflet-control-locate-location-arrow",
      iconLoading: "leaflet-control-locate-spinner",
      /** The element to be created for icons. For example span or i */
      iconElementTag: "span",
      /** The element to be created for the text. For example small or span */
      textElementTag: "small",
      /** Padding around the accuracy circle. */
      circlePadding: [0, 0],
      /** Use metric units. */
      metric: true,
      /**
       * This callback can be used in case you would like to override button creation behavior.
       * This is useful for DOM manipulation frameworks such as angular etc.
       * This function should return an object with HtmlElement for the button (link property) and the icon (icon property).
       */
      createButtonCallback(container, options) {
        const link = L.DomUtil.create("a", "leaflet-bar-part leaflet-bar-part-single", container);
        link.title = options.strings.title;
        link.href = "#";
        link.setAttribute("role", "button");
        const icon = L.DomUtil.create(options.iconElementTag, options.icon, link);

        if (options.strings.text !== undefined) {
          const text = L.DomUtil.create(options.textElementTag, "leaflet-locate-text", link);
          text.textContent = options.strings.text;
          link.classList.add("leaflet-locate-text-active");
          link.parentNode.style.display = "flex";
          if (options.icon.length > 0) {
            icon.classList.add("leaflet-locate-icon");
          }
        }

        return { link, icon };
      },
      /** This event is called in case of any location error that is not a time out error. */
      onLocationError(err, control) {
        alert(err.message);
      },
      /**
       * This event is called when the user's location is outside the bounds set on the map.
       * The event is called repeatedly when the location changes.
       */
      onLocationOutsideMapBounds(control) {
        control.stop();
        alert(control.options.strings.outsideMapBoundsMsg);
      },
      /** Display a pop-up when the user click on the inner marker. */
      showPopup: true,
      strings: {
        title: "Show me where I am",
        metersUnit: "meters",
        feetUnit: "feet",
        popup: "You are within {distance} {unit} from this point",
        outsideMapBoundsMsg: "You seem located outside the boundaries of the map"
      },
      /** The default options passed to leaflets locate method. */
      locateOptions: {
        maxZoom: Infinity,
        watch: true, // if you overwrite this, visualization cannot be updated
        setView: false // have to set this to false because we have to
        // do setView manually
      }
    },

    initialize(options) {
      // set default options if nothing is set (merge one step deep)
      for (const i in options) {
        if (typeof this.options[i] === "object") {
          L.extend(this.options[i], options[i]);
        } else {
          this.options[i] = options[i];
        }
      }

      // extend the follow marker style and circle from the normal style
      this.options.followMarkerStyle = L.extend({}, this.options.markerStyle, this.options.followMarkerStyle);
      this.options.followCircleStyle = L.extend({}, this.options.circleStyle, this.options.followCircleStyle);
      this.options.followCompassStyle = L.extend({}, this.options.compassStyle, this.options.followCompassStyle);
    },

    /**
     * Add control to map. Returns the container for the control.
     */
    onAdd(map) {
      const container = L.DomUtil.create("div", "leaflet-control-locate leaflet-bar leaflet-control");
      this._container = container;
      this._map = map;
      this._layer = this.options.layer || new L.LayerGroup();
      this._layer.addTo(map);
      this._event = undefined;
      this._compassHeading = null;
      this._prevBounds = null;

      const linkAndIcon = this.options.createButtonCallback(container, this.options);
      this._link = linkAndIcon.link;
      this._icon = linkAndIcon.icon;

      L.DomEvent.on(
        this._link,
        "click",
        function (ev) {
          L.DomEvent.stopPropagation(ev);
          L.DomEvent.preventDefault(ev);
          this._onClick();
        },
        this
      ).on(this._link, "dblclick", L.DomEvent.stopPropagation);

      this._resetVariables();

      this._map.on("unload", this._unload, this);

      return container;
    },

    /**
     * This method is called when the user clicks on the control.
     */
    _onClick() {
      this._justClicked = true;
      const wasFollowing = this._isFollowing();
      this._userPanned = false;
      this._userZoomed = false;

      if (this._active && !this._event) {
        // click while requesting
        this.stop();
      } else if (this._active) {
        const behaviors = this.options.clickBehavior;
        let behavior = behaviors.outOfView;
        if (this._map.getBounds().contains(this._event.latlng)) {
          behavior = wasFollowing ? behaviors.inView : behaviors.inViewNotFollowing;
        }

        // Allow inheriting from another behavior
        if (behaviors[behavior]) {
          behavior = behaviors[behavior];
        }

        switch (behavior) {
          case "setView":
            this.setView();
            break;
          case "stop":
            this.stop();
            if (this.options.returnToPrevBounds) {
              const f = this.options.flyTo ? this._map.flyToBounds : this._map.fitBounds;
              f.bind(this._map)(this._prevBounds);
            }
            break;
        }
      } else {
        if (this.options.returnToPrevBounds) {
          this._prevBounds = this._map.getBounds();
        }
        this.start();
      }

      this._updateContainerStyle();
    },

    /**
     * Starts the plugin:
     * - activates the engine
     * - draws the marker (if coordinates available)
     */
    start() {
      this._activate();

      if (this._event) {
        this._drawMarker(this._map);

        // if we already have a location but the user clicked on the control
        if (this.options.setView) {
          this.setView();
        }
      }
      this._updateContainerStyle();
    },

    /**
     * Stops the plugin:
     * - deactivates the engine
     * - reinitializes the button
     * - removes the marker
     */
    stop() {
      this._deactivate();

      this._cleanClasses();
      this._resetVariables();

      this._removeMarker();
    },

    /**
     * Keep the control active but stop following the location
     */
    stopFollowing() {
      this._userPanned = true;
      this._updateContainerStyle();
      this._drawMarker();
    },

    /**
     * This method launches the location engine.
     * It is called before the marker is updated,
     * event if it does not mean that the event will be ready.
     *
     * Override it if you want to add more functionalities.
     * It should set the this._active to true and do nothing if
     * this._active is true.
     */
    _activate() {
      if (this._active || !this._map) {
        return;
      }

      this._map.locate(this.options.locateOptions);
      this._map.fire("locateactivate", this);
      this._active = true;

      // bind event listeners
      this._map.on("locationfound", this._onLocationFound, this);
      this._map.on("locationerror", this._onLocationError, this);
      this._map.on("dragstart", this._onDrag, this);
      this._map.on("zoomstart", this._onZoom, this);
      this._map.on("zoomend", this._onZoomEnd, this);
      if (this.options.showCompass) {
        const oriAbs = "ondeviceorientationabsolute" in window;
        if (oriAbs || "ondeviceorientation" in window) {
          const _this = this;
          const deviceorientation = function () {
            L.DomEvent.on(window, oriAbs ? "deviceorientationabsolute" : "deviceorientation", _this._onDeviceOrientation, _this);
          };
          if (DeviceOrientationEvent && typeof DeviceOrientationEvent.requestPermission === "function") {
            DeviceOrientationEvent.requestPermission().then(function (permissionState) {
              if (permissionState === "granted") {
                deviceorientation();
              }
            });
          } else {
            deviceorientation();
          }
        }
      }
    },

    /**
     * Called to stop the location engine.
     *
     * Override it to shutdown any functionalities you added on start.
     */
    _deactivate() {
      if (!this._active || !this._map) {
        return;
      }

      this._map.stopLocate();
      this._map.fire("locatedeactivate", this);
      this._active = false;

      if (!this.options.cacheLocation) {
        this._event = undefined;
      }

      // unbind event listeners
      this._map.off("locationfound", this._onLocationFound, this);
      this._map.off("locationerror", this._onLocationError, this);
      this._map.off("dragstart", this._onDrag, this);
      this._map.off("zoomstart", this._onZoom, this);
      this._map.off("zoomend", this._onZoomEnd, this);
      if (this.options.showCompass) {
        this._compassHeading = null;
        if ("ondeviceorientationabsolute" in window) {
          L.DomEvent.off(window, "deviceorientationabsolute", this._onDeviceOrientation, this);
        } else if ("ondeviceorientation" in window) {
          L.DomEvent.off(window, "deviceorientation", this._onDeviceOrientation, this);
        }
      }
    },

    /**
     * Zoom (unless we should keep the zoom level) and an to the current view.
     */
    setView() {
      this._drawMarker();
      if (this._isOutsideMapBounds()) {
        this._event = undefined; // clear the current location so we can get back into the bounds
        this.options.onLocationOutsideMapBounds(this);
      } else {
        if (this._justClicked && this.options.initialZoomLevel !== false) {
          var f = this.options.flyTo ? this._map.flyTo : this._map.setView;
          f.bind(this._map)([this._event.latitude, this._event.longitude], this.options.initialZoomLevel);
        } else if (this.options.keepCurrentZoomLevel) {
          var f = this.options.flyTo ? this._map.flyTo : this._map.panTo;
          f.bind(this._map)([this._event.latitude, this._event.longitude]);
        } else {
          var f = this.options.flyTo ? this._map.flyToBounds : this._map.fitBounds;
          // Ignore zoom events while setting the viewport as these would stop following
          this._ignoreEvent = true;
          f.bind(this._map)(this.options.getLocationBounds(this._event), {
            padding: this.options.circlePadding,
            maxZoom: this.options.initialZoomLevel || this.options.locateOptions.maxZoom
          });
          L.Util.requestAnimFrame(function () {
            // Wait until after the next animFrame because the flyTo can be async
            this._ignoreEvent = false;
          }, this);
        }
      }
    },

    /**
     *
     */
    _drawCompass() {
      if (!this._event) {
        return;
      }

      const latlng = this._event.latlng;

      if (this.options.showCompass && latlng && this._compassHeading !== null) {
        const cStyle = this._isFollowing() ? this.options.followCompassStyle : this.options.compassStyle;
        if (!this._compass) {
          this._compass = new this.options.compassClass(latlng, this._compassHeading, cStyle).addTo(this._layer);
        } else {
          this._compass.setLatLng(latlng);
          this._compass.setHeading(this._compassHeading);
          // If the compassClass can be updated with setStyle, update it.
          if (this._compass.setStyle) {
            this._compass.setStyle(cStyle);
          }
        }
        //
      }
      if (this._compass && (!this.options.showCompass || this._compassHeading === null)) {
        this._compass.removeFrom(this._layer);
        this._compass = null;
      }
    },

    /**
     * Draw the marker and accuracy circle on the map.
     *
     * Uses the event retrieved from onLocationFound from the map.
     */
    _drawMarker() {
      if (this._event.accuracy === undefined) {
        this._event.accuracy = 0;
      }

      const radius = this._event.accuracy;
      const latlng = this._event.latlng;

      // circle with the radius of the location's accuracy
      if (this.options.drawCircle) {
        const style = this._isFollowing() ? this.options.followCircleStyle : this.options.circleStyle;

        if (!this._circle) {
          this._circle = L.circle(latlng, radius, style).addTo(this._layer);
        } else {
          this._circle.setLatLng(latlng).setRadius(radius).setStyle(style);
        }
      }

      let distance;
      let unit;
      if (this.options.metric) {
        distance = radius.toFixed(0);
        unit = this.options.strings.metersUnit;
      } else {
        distance = (radius * 3.2808399).toFixed(0);
        unit = this.options.strings.feetUnit;
      }

      // small inner marker
      if (this.options.drawMarker) {
        const mStyle = this._isFollowing() ? this.options.followMarkerStyle : this.options.markerStyle;
        if (!this._marker) {
          this._marker = new this.options.markerClass(latlng, mStyle).addTo(this._layer);
        } else {
          this._marker.setLatLng(latlng);
          // If the markerClass can be updated with setStyle, update it.
          if (this._marker.setStyle) {
            this._marker.setStyle(mStyle);
          }
        }
      }

      this._drawCompass();

      const t = this.options.strings.popup;
      function getPopupText() {
        if (typeof t === "string") {
          return L.Util.template(t, { distance, unit });
        } else if (typeof t === "function") {
          return t({ distance, unit });
        } else {
          return t;
        }
      }
      if (this.options.showPopup && t && this._marker) {
        this._marker.bindPopup(getPopupText())._popup.setLatLng(latlng);
      }
      if (this.options.showPopup && t && this._compass) {
        this._compass.bindPopup(getPopupText())._popup.setLatLng(latlng);
      }
    },

    /**
     * Remove the marker from map.
     */
    _removeMarker() {
      this._layer.clearLayers();
      this._marker = undefined;
      this._circle = undefined;
    },

    /**
     * Unload the plugin and all event listeners.
     * Kind of the opposite of onAdd.
     */
    _unload() {
      this.stop();
      // May become undefined during HMR
      if (this._map) {
        this._map.off("unload", this._unload, this);
      }
    },

    /**
     * Sets the compass heading
     */
    _setCompassHeading(angle) {
      if (!isNaN(parseFloat(angle)) && isFinite(angle)) {
        angle = Math.round(angle);

        this._compassHeading = angle;
        L.Util.requestAnimFrame(this._drawCompass, this);
      } else {
        this._compassHeading = null;
      }
    },

    /**
     * If the compass fails calibration just fail safely and remove the compass
     */
    _onCompassNeedsCalibration() {
      this._setCompassHeading();
    },

    /**
     * Process and normalise compass events
     */
    _onDeviceOrientation(e) {
      if (!this._active) {
        return;
      }

      if (e.webkitCompassHeading) {
        // iOS
        this._setCompassHeading(e.webkitCompassHeading);
      } else if (e.absolute && e.alpha) {
        // Android
        this._setCompassHeading(360 - e.alpha);
      }
    },

    /**
     * Calls deactivate and dispatches an error.
     */
    _onLocationError(err) {
      // ignore time out error if the location is watched
      if (err.code == 3 && this.options.locateOptions.watch) {
        return;
      }

      this.stop();
      this.options.onLocationError(err, this);
    },

    /**
     * Stores the received event and updates the marker.
     */
    _onLocationFound(e) {
      // no need to do anything if the location has not changed
      if (this._event && this._event.latlng.lat === e.latlng.lat && this._event.latlng.lng === e.latlng.lng && this._event.accuracy === e.accuracy) {
        return;
      }

      if (!this._active) {
        // we may have a stray event
        return;
      }

      this._event = e;

      this._drawMarker();
      this._updateContainerStyle();

      switch (this.options.setView) {
        case "once":
          if (this._justClicked) {
            this.setView();
          }
          break;
        case "untilPan":
          if (!this._userPanned) {
            this.setView();
          }
          break;
        case "untilPanOrZoom":
          if (!this._userPanned && !this._userZoomed) {
            this.setView();
          }
          break;
        case "always":
          this.setView();
          break;
        case false:
          // don't set the view
          break;
      }

      this._justClicked = false;
    },

    /**
     * When the user drags. Need a separate event so we can bind and unbind event listeners.
     */
    _onDrag() {
      // only react to drags once we have a location
      if (this._event && !this._ignoreEvent) {
        this._userPanned = true;
        this._updateContainerStyle();
        this._drawMarker();
      }
    },

    /**
     * When the user zooms. Need a separate event so we can bind and unbind event listeners.
     */
    _onZoom() {
      // only react to drags once we have a location
      if (this._event && !this._ignoreEvent) {
        this._userZoomed = true;
        this._updateContainerStyle();
        this._drawMarker();
      }
    },

    /**
     * After a zoom ends update the compass and handle sideways zooms
     */
    _onZoomEnd() {
      if (this._event) {
        this._drawCompass();
      }

      if (this._event && !this._ignoreEvent) {
        // If we have zoomed in and out and ended up sideways treat it as a pan
        if (this._marker && !this._map.getBounds().pad(-0.3).contains(this._marker.getLatLng())) {
          this._userPanned = true;
          this._updateContainerStyle();
          this._drawMarker();
        }
      }
    },

    /**
     * Compute whether the map is following the user location with pan and zoom.
     */
    _isFollowing() {
      if (!this._active) {
        return false;
      }

      if (this.options.setView === "always") {
        return true;
      } else if (this.options.setView === "untilPan") {
        return !this._userPanned;
      } else if (this.options.setView === "untilPanOrZoom") {
        return !this._userPanned && !this._userZoomed;
      }
    },

    /**
     * Check if location is in map bounds
     */
    _isOutsideMapBounds() {
      if (this._event === undefined) {
        return false;
      }
      return this._map.options.maxBounds && !this._map.options.maxBounds.contains(this._event.latlng);
    },

    /**
     * Toggles button class between following and active.
     */
    _updateContainerStyle() {
      if (!this._container) {
        return;
      }

      if (this._active && !this._event) {
        // active but don't have a location yet
        this._setClasses("requesting");
      } else if (this._isFollowing()) {
        this._setClasses("following");
      } else if (this._active) {
        this._setClasses("active");
      } else {
        this._cleanClasses();
      }
    },

    /**
     * Sets the CSS classes for the state.
     */
    _setClasses(state) {
      if (state == "requesting") {
        removeClasses(this._container, "active following");
        addClasses(this._container, "requesting");

        removeClasses(this._icon, this.options.icon);
        addClasses(this._icon, this.options.iconLoading);
      } else if (state == "active") {
        removeClasses(this._container, "requesting following");
        addClasses(this._container, "active");

        removeClasses(this._icon, this.options.iconLoading);
        addClasses(this._icon, this.options.icon);
      } else if (state == "following") {
        removeClasses(this._container, "requesting");
        addClasses(this._container, "active following");

        removeClasses(this._icon, this.options.iconLoading);
        addClasses(this._icon, this.options.icon);
      }
    },

    /**
     * Removes all classes from button.
     */
    _cleanClasses() {
      L.DomUtil.removeClass(this._container, "requesting");
      L.DomUtil.removeClass(this._container, "active");
      L.DomUtil.removeClass(this._container, "following");

      removeClasses(this._icon, this.options.iconLoading);
      addClasses(this._icon, this.options.icon);
    },

    /**
     * Reinitializes state variables.
     */
    _resetVariables() {
      // whether locate is active or not
      this._active = false;

      // true if the control was clicked for the first time
      // we need this so we can pan and zoom once we have the location
      this._justClicked = false;

      // true if the user has panned the map after clicking the control
      this._userPanned = false;

      // true if the user has zoomed the map after clicking the control
      this._userZoomed = false;
    }
  });

  L.control.locate = (options) => new L.Control.Locate(options);

  return LocateControl;
}, window);