Robust array type check for cross-frame support

In a multi-frame DOM environment, if setView is called with an array for the first parameter, a subsequent call to getBounds raises "Invalid LatLng object" exception. This is the case if the array passed to setView was created outside the iFrame that contains the map. It causes the array test using "instanceof" in L.latLng to fail, and _initialTopLeftPoint to not being properly initialized. Thank you to Juriy Zaytsev for the full explaination: http://perfectionkills.com/instanceof-considered-harmful-or-how-to-write-a-robust-isarray/ John Resig and Dean Edwards post comments and concur.
Leaflet · mourner · Jan 14, 2013 · Jan 14, 2013 · Jan 14, 2013 · 7dd7e4f69962b20c7e3a48b5441800534628ee2b
commit 7dd7e4f69962b20c7e3a48b5441800534628ee2b
diff --git a/src/core/Util.js b/src/core/Util.js
@@ -97,6 +97,10 @@ L.Util = {
 		});
 	},
 
+	isArray: function (obj) {
+		return (Object.prototype.toString.call(obj) === '[object Array]');
+	},
+
 	emptyImageUrl: 'data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs='
 };
 

diff --git a/src/geo/LatLng.js b/src/geo/LatLng.js
@@ -74,7 +74,7 @@ L.latLng = function (a, b) { // (LatLng) or ([Number, Number]) or (Number, Numbe
 	if (a instanceof L.LatLng) {
 		return a;
 	}
-	if (a instanceof Array) {
+	if (L.Util.isArray(a)) {
 		return new L.LatLng(a[0], a[1]);
 	}
 	if (isNaN(a)) {

diff --git a/src/geometry/Point.js b/src/geometry/Point.js
@@ -100,7 +100,7 @@ L.point = function (x, y, round) {
 	if (x instanceof L.Point) {
 		return x;
 	}
-	if (x instanceof Array) {
+	if (L.Util.isArray(x)) {
 		return new L.Point(x[0], x[1]);
 	}
 	if (isNaN(x)) {

diff --git a/src/layer/GeoJSON.js b/src/layer/GeoJSON.js
@@ -15,7 +15,7 @@ L.GeoJSON = L.FeatureGroup.extend({
 	},
 
 	addData: function (geojson) {
-		var features = geojson instanceof Array ? geojson : geojson.features,
+		var features = L.Util.isArray(geojson) ? geojson : geojson.features,
 		    i, len;
 
 		if (features) {

diff --git a/src/layer/vector/Polygon.js b/src/layer/vector/Polygon.js
@@ -10,7 +10,7 @@ L.Polygon = L.Polyline.extend({
 	initialize: function (latlngs, options) {
 		L.Polyline.prototype.initialize.call(this, latlngs, options);
 
-		if (latlngs && (latlngs[0] instanceof Array) && (typeof latlngs[0][0] !== 'number')) {
+		if (latlngs && L.Util.isArray(latlngs[0]) && (typeof latlngs[0][0] !== 'number')) {
 			this._latlngs = this._convertLatLngs(latlngs[0]);
 			this._holes = latlngs.slice(1);
 		}

diff --git a/src/layer/vector/Polyline.js b/src/layer/vector/Polyline.js
@@ -88,7 +88,7 @@ L.Polyline = L.Path.extend({
 	_convertLatLngs: function (latlngs) {
 		var i, len;
 		for (i = 0, len = latlngs.length; i < len; i++) {
-			if (latlngs[i] instanceof Array && typeof latlngs[i][0] !== 'number') {
+			if (L.Util.isArray(latlngs[i]) && typeof latlngs[i][0] !== 'number') {
 				return;
 			}
 			latlngs[i] = L.latLng(latlngs[i]);

diff --git a/src/map/Map.js b/src/map/Map.js
@@ -466,7 +466,7 @@ L.Map = L.Class.extend({
 	},
 
 	_initLayers: function (layers) {
-		layers = layers ? (layers instanceof Array ? layers : [layers]) : [];
+		layers = layers ? (L.Util.isArray(layers) ? layers : [layers]) : [];
 
 		this._layers = {};
 		this._zoomBoundLayers = {};
-Original file line number
+Diff line change
@@ Expand Up / @@ -97,6 +97,10 @@ L.Util = { @@
     		});
     	},
+    	isArray: function (obj) {
+    		return (Object.prototype.toString.call(obj) === '[object Array]');
+    	},
     	emptyImageUrl: 'data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs='
     };
@@ Expand Down @@