code: function () {
  		var hash = window.location.hash;
  		var filterIndex = hash.indexOf('filter=');
  		if (filterIndex !== -1) {
  			var filterString = hash.substr(filterIndex + 7).trim();
  			var visible = layersControl.filter(filterString);
  
  			// enable first layer as actual layer.
  			var first = Object.keys(visible)[0];
  			if (first in baseLayers) {
  				map.addLayer(baseLayers[first]);
  				map.eachLayer(function (layer) {
  					if (layer._providerName !== first) {
  						map.removeLayer(layer);
  					}
  				});
  				layersControl.filter(filterString);
  			}
  		}
  	}
docs: Pass a filter in the hash tag to show only layers containing that string for example: #filter=Open