Leaflet minimal map

HTML

<script src="https://unpkg.com/[email protected]/dist/leaflet.js"></script>
<link rel="stylesheet" href="https://unpkg.com/[email protected]/dist/leaflet.css">
<div id="map"></div>

CSS

#map { 
    height: 400px; 
}

JavaScript

var osm = new L.TileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
			maxZoom: 20,
			subdomains: 'abc',
			isElliptical : false,
			attribution: "© данные <a href='http://openstreetmap.org'>OpenStreetMap</a>"
		});

		var yandex = L.tileLayer(
		  'http://vec{s}.maps.yandex.net/tiles?l=map&v=4.55.2&z={z}&x={x}&y={y}&scale=2&lang=ru_RU', {
			subdomains: ['01', '02', '03', '04'],
			attribution: '<a http="yandex.ru" target="_blank">Яндекс</a>',
			reuseTiles: true,
			isElliptical : true,
			updateWhenIdle: false
		});
		
		var mts_lte = new L.TileLayer('http://tiles.mts.ru/LTE_New/{z}/{x}/{y}', {
			maxZoom: 20,
			isElliptical : true,
			subdomains: 'abc',
			attribution: "© <a href='http://www.mts.ru/mobil_inet_and_tv/help/mts/coverage/' target='_blank'>Данные МТС</a>"
		});

		var baseLayers = {
			"Yandex": yandex,
			"OSM":osm
		};

		var overlays = {
			"MTS LTE": mts_lte
		};
		
		var map = L.map('map', {center: L.latLng(56.83559,35.89354),zoom: 10});
		map.on('baselayerchange', function (e) {
			var center = map.getCenter();
			var zoom = map.getZoom();
			
			//L.CRS.EPSG3857 // OSM, Google, Bing etc.
			//L.CRS.EPSG3395 // Yandex elliptical
			map.options.crs = e.layer.options.isElliptical ? L.CRS.EPSG3395 : L.CRS.EPSG3857;
			map._resetView(center, zoom, false, false);
		});
		
		map.on('overlayadd', function(eo) {
			mts_lte.options.crs = L.CRS.EPSG3395; // NOT WORKING (no this options for overlays?)
			//console.log(eo);
		});
		
		L.control.layers(baseLayers, overlays, { collapsed: false }).addTo(map);
		
		map.addLayer(yandex);