Control.Zoom.js

/*
 * L.Control.Zoom is used for the default zoom buttons on the map.
 */

L.Control.Zoom = L.Control.extend({
	options: {
		position: 'topleft'
	},

	onAdd: function (map) {
		var zoomName = 'leaflet-control-zoom',
		    container = L.DomUtil.create('div', zoomName + ' leaflet-bar');

		this._map = map;

		this._zoomInButton  = this._createButton(
		        '+', 'Zoom in',  zoomName + '-in',  container, this._zoomIn,  this);
		this._zoomOutButton = this._createButton(
		        '-', 'Zoom out', zoomName + '-out', container, this._zoomOut, this);

		map.on('zoomend baselayerchange', this._updateDisabled, this);

		return container;
	},

	onRemove: function (map) {
		map.off('zoomend baselayerchange', this._updateDisabled, this);
	},

	_zoomIn: function (e) {
		this._map.zoomIn(e.shiftKey ? 3 : 1);
	},

	_zoomOut: function (e) {
		this._map.zoomOut(e.shiftKey ? 3 : 1);
	},

	_createButton: function (html, title, className, container, fn, context) {
		var link = L.DomUtil.create('a', className, container);
		link.innerHTML = html;
		link.href = '#';
		link.title = title;

		var stop = L.DomEvent.stopPropagation;

		L.DomEvent
		    .on(link, 'click', stop)
		    .on(link, 'mousedown', stop)
		    .on(link, 'dblclick', stop)
		    .on(link, 'click', L.DomEvent.preventDefault)
		    .on(link, 'click', fn, context);

		return link;
	},

	_updateDisabled: function () {
		var map = this._map,
			className = 'leaflet-disabled';

		L.DomUtil.removeClass(this._zoomInButton, className);
		L.DomUtil.removeClass(this._zoomOutButton, className);

		if (map._zoom === map.getMinZoom()) {
			L.DomUtil.addClass(this._zoomOutButton, className);
		}
		if (map._zoom === map.getMaxZoom()) {
			L.DomUtil.addClass(this._zoomInButton, className);
		}
	}
});

L.Map.mergeOptions({
	zoomControl: true
});

L.Map.addInitHook(function () {
	if (this.options.zoomControl) {
		this.zoomControl = new L.Control.Zoom();
		this.addControl(this.zoomControl);
	}
});

L.control.zoom = function (options) {
	return new L.Control.Zoom(options);
};