Using Proj4Leaflet with a GeoJSON layer

1.0.0b2 version

HTML

<script src="//cdn.leafletjs.com/leaflet/v1.0.0-beta.2/leaflet.js"></script>
<link rel="stylesheet" href="//cdn.leafletjs.com/leaflet/v1.0.0-beta.2/leaflet.css">
<script src="//rawgit.com/kartena/Proj4Leaflet/leaflet-proj-refactor/lib/proj4-compressed.js"></script>
<script src="//rawgit.com/kartena/Proj4Leaflet/leaflet-proj-refactor/src/proj4leaflet.js"></script>
<div id="map" class="map"></div>

CSS

html, body {
    height: 100%;
    width: 100%;
    padding: 0;
    margin: 0;
    border: 0;
    }
.map {
	height: 100%;
	width: 100%;
    }

JavaScript

var map = L.map('map', {
    center: [53.2, -1.7],
    zoom: 6
});

var lDarkMatter = L.tileLayer('https://cartodb-basemaps-{s}.global.ssl.fastly.net/dark_nolabels/{z}/{x}/{y}.png');
map.addLayer(lDarkMatter);

var sampleGeographic = {
	"type": "FeatureCollection",
	"crs": {
		"type": "name",
		"properties": {
			"name": "urn:ogc:def:crs:OGC:1.3:CRS84"
		}
	},
	"features": [{
		"type": "Feature",
		"properties": {

		},
		"geometry": {
			"type": "Polygon",
			"coordinates": [[
			[-5.61, 50.11],
			[-2.73,	51.42],
			[-4.90,	51.82],
			[-4.00,	53.37],
			[-2.51,	53.39],
			[-3.22,	54.87],
			[-1.89,	55.63],
			[0.56,	52.85],
			[1.98,	52.59],
			[0.81,	51.44],
			[1.91,	51.34],
			[-5.61,	50.11]]]
		}
	}]
};

var sampleProjected = {
    "type": "FeatureCollection",
    "crs": {
        "type": "name",
        "properties": {
            "name": "urn:ogc:def:crs:EPSG::3857"
        }
    },
    "features": [{
        "type": "Feature",
        "properties": {

        },
        "geometry": {
            "type": "Polygon",
            "coordinates": [[
            [-625570.6, 6465993.0],
            [-305006.9, 6696510.8],
            [-546330.2, 6768547.6],
            [-445478.6, 7053093.0],
            [-279794.0, 7056694.8],
            [-359034.5, 7337638.4],
            [-211359.0, 7485313.8],
            [62380.8,   6955843.3],
            [220861.7,  6909019.4],
            [91195.5,   6700112.6],
            [213658.1,  6682103.4],
            [-625570.6, 6465993.0]]]
        }
    }]
};

var dashedStyle = {
        weight: 2,
        opacity: 1,
        fillOpacity: 0,
        color: 'white',
        dashArray: '3'
    };
var dashedStyle1 = {
        weight: 2,
        opacity: 1,
        fillOpacity: 1,
        color: 'red',
        dashArray: '3'
    };
var layerGeographic = L.geoJson(sampleGeographic, {style:dashedStyle}).addTo(map);

var layerProjected = L.Proj.geoJson(sampleProjected,{style:dashedStyle}).addTo(map);