How to use the leaflet.Browser function in leaflet

export function initMap() {
  // Initalize Leaflet
  map = L.map('map', {
    zoomControl: false,
    attributionControl: false,
    maxZoom: 20,
    keyboardZoomOffset: 0.05,
    // Enables fractional zoom.
    zoomSnap: 0,
    // Prevents scroll wheel zoom when iframed.
    scrollWheelZoom: (window.self === window.top),
    // If iframed & touchscreen, disable dragging & tap to prevent Leaflet
    // from hijacking the page scroll.
    dragging: !(window.self !== window.top && L.Browser.touch),
    tap: !(window.self !== window.top && L.Browser.touch),
  });

  // Provide alternate zoom in/zoom out button controls in embedded version
  // since, when iframed, the scroll wheel zoom will no longer work.
  if (store.getState().app.isEmbedded === true) {
    const zoomControl = L.control.zoom();
    zoomControl.addTo(map);
  }

  // Get map start position
  getMapStartLocation()
    .then((mapStartLocation) => {
      // Create Leaflet map
      map.setView(mapStartLocation.latlng, mapStartLocation.zoom);

onAdd: function (map) {
		this._map = map;

        // don't animate on browsers without hardware-accelerated transitions or old Android/Opera
		if (typeof this._zoomAnimated == 'undefined') // Leaflet 0.7
			this._zoomAnimated = L.DomUtil.TRANSITION && L.Browser.any3d && !L.Browser.mobileOpera && this._map.options.zoomAnimation;

		if (L.version < '1.0') this._map.on(this.getEvents(), this);
		if (!this._div) {
			this._div = L.DomUtil.create('div', 'leaflet-image-layer');
			if (this.options.pointerEvents) {
				this._div.style['pointer-events'] = this.options.pointerEvents;
			}
			if (typeof this.options.zIndex !== 'undefined') {
				this._div.style.zIndex = this.options.zIndex;
			}
			if (typeof this.options.opacity !== 'undefined') {
				this._div.style.opacity = this.options.opacity;
			}
		}

		this.getPane().appendChild(this._div);

var container = this._container

    var size = b.getSize()

    var m = L.Browser.retina ? 2 : 1

    L.DomUtil.setPosition(container, b.min)

    // set canvas size (also clearing it); use double size on retina
    container.width = m * size.x
    container.height = m * size.y
    container.style.width = size.x + 'px'
    container.style.height = size.y + 'px'

    if (L.Browser.retina) {
      this._ctx.scale(2, 2)
    }

    // translate so we use the same path coordinates after canvas element moves
    this._ctx.translate(-b.min.x, -b.min.y)

    // Tell paths to redraw themselves
    this.fire('update')
  }
})

mouseover: (e) => {
        const layer = e.target;
        // bring layer to front if not older browser
        if (!L.Browser.ie && !L.Browser.opera) {
          layer.bringToFront();
        }
        this._showTooltip(feature);
      },
      mouseout: () => {

export function initMap() {
  // Initalize Leaflet
  map = L.map('map', {
    zoomControl: false,
    attributionControl: false,
    maxZoom: 20,
    keyboardZoomOffset: 0.05,
    // Enables fractional zoom.
    zoomSnap: 0,
    // Prevents scroll wheel zoom when iframed.
    scrollWheelZoom: (window.self === window.top),
    // If iframed & touchscreen, disable dragging & tap to prevent Leaflet
    // from hijacking the page scroll.
    dragging: !(window.self !== window.top && L.Browser.touch),
    tap: !(window.self !== window.top && L.Browser.touch),
  });

  // Provide alternate zoom in/zoom out button controls in embedded version
  // since, when iframed, the scroll wheel zoom will no longer work.
  if (store.getState().app.isEmbedded === true) {
    const zoomControl = L.control.zoom();
    zoomControl.addTo(map);
  }

  // Get map start position
  getMapStartLocation()
    .then((mapStartLocation) => {
      // Create Leaflet map
      map.setView(mapStartLocation.latlng, mapStartLocation.zoom);

      // Add leaflet-hash (forked version)

initialize: function(url, options) {
    this.options.crs.wrapLat = this.options.crs.wrapLng =  null
    L.TileLayer.prototype.initialize.call(this, url, options)

    this._adjustForRetina = this.options.detectRetina && L.Browser.retina
    this._computeImageAndGridSize()
    this.on('tileload', this._adjustNonSquareTile)
  },

var L = require('leaflet');
var geometry = require('./geometry');
var ControlMarker = require('./marker');
var Endpoint = require('./endpoint');
var Selection = require('./selection');
var Rbush = global.Rbush || require('rbush');

var START = L.Browser.touch ? 'touchstart mousedown' : 'mousedown';

/**
 * LineString select control
 *
 * @class  L.Control.LineStringSelect
 * @extends {L.Control}
 */
var Select = L.Control.extend( /**  @lends Select.prototype */ {

  statics: {
    Selection: Selection,
    Endpoint: Endpoint,
    ControlMarker: ControlMarker
  },

  /**

setViewToBounds: function(bounds, immediate) {
            if (bounds && bounds.isValid()) {
                bounds = wrapLatLngBoundsToTarget(bounds, this.map.getCenter());
                if (L.Browser.mobile || immediate) {
                    this.map.fitBounds(bounds, {maxZoom: 16});
                } else {
                    this.map.flyToBounds(bounds, {maxZoom: 16});
                }
            }
        },

_initImage: function () {
		var _image = L.DomUtil.create('img', 'leaflet-image-layer');

		this._div.appendChild(_image);

		if (this._map.options.zoomAnimation && L.Browser.any3d) {
			L.DomUtil.addClass(_image, 'leaflet-zoom-animated');
		} else {
			L.DomUtil.addClass(_image, 'leaflet-zoom-hide');
		}


        //TODO createImage util method to remove duplication
		L.extend(_image, {
			galleryimg: 'no',
			onselectstart: L.Util.falseFn,
			onmousemove: L.Util.falseFn,
			onload: L.bind(this._onImageLoad, this),
			onerror: L.bind(this._onImageError, this)
		});

		return _image;

_initContainer: function () {
        var parentContainer = this.getPane();
        var animated = this._map.options.zoomAnimation && L.Browser.any3d;
        var className = 'themeLayer leaflet-layer leaflet-zoom-' + (animated ? 'animated' : 'hide');
        this.container = L.DomUtil.create("div", className, parentContainer);

        var originProp = L.DomUtil.testProp(['transformOrigin', 'WebkitTransformOrigin', 'msTransformOrigin']);
        this.container.id = this.options.id;
        this.container.style[originProp] = '50% 50%';

        this.container.style.position = "absolute";
        this.container.style.zIndex = 200;
    },