Merge pull request #3455 from Leaflet/polyline-isempty

Add Polyline/Polygon.isEmpty method

spec/suites/layer/vector/PolygonSpec.js

@@ -75,6 +75,30 @@ describe('Polygon', function () {
 
 	});
 
+	describe("#isEmpty", function () {
+
+		it('should return true for a polygon with no latlngs', function () {
+			var layer = new L.Polygon([]);
+			expect(layer.isEmpty()).to.be(true);
+		});
+
+		it('should return false for simple polygon', function () {
+			var latLngs = [[1, 2], [3, 4], [5, 6]];
+			var layer = new L.Polygon(latLngs);
+			expect(layer.isEmpty()).to.be(false);
+		});
+
+		it('should return false for a multi-polygon', function () {
+			var latLngs = [
+				[[[10, 20], [30, 40], [50, 60]]],
+				[[[0, 10], [10, 10], [10, 0]], [[2, 3], [2, 4], [3, 4]]]
+			];
+			var layer = new L.Polygon(latLngs);
+			expect(layer.isEmpty()).to.be(false);
+		});
+
+	});
+
 	describe("#setLatLngs", function () {
 		it("doesn't overwrite the given latlng array", function () {
 			var originalLatLngs = [

spec/suites/layer/vector/PolylineSpec.js

@@ -49,6 +49,30 @@ describe('Polyline', function () {
 
 	});
 
+	describe("#isEmpty", function () {
+
+		it('should return true for a polyline with no latlngs', function () {
+			var polyline = new L.Polyline([]);
+			expect(polyline.isEmpty()).to.be(true);
+		});
+
+		it('should return false for simple polyline', function () {
+			var latLngs = [[1, 2], [3, 4]];
+			var polyline = new L.Polyline(latLngs);
+			expect(polyline.isEmpty()).to.be(false);
+		});
+
+		it('should return false for multi-polyline', function () {
+			var latLngs = [
+				[[1, 2], [3, 4]],
+				[[11, 12], [13, 14]]
+			];
+			var polyline = new L.Polyline(latLngs);
+			expect(polyline.isEmpty()).to.be(false);
+		});
+
+	});
+
 	describe("#setLatLngs", function () {
 		it("doesn't overwrite the given latlng array", function () {
 			var originalLatLngs = [

src/layer/vector/Polygon.js

@@ -8,6 +8,10 @@ L.Polygon = L.Polyline.extend({
 		fill: true
 	},
 
+	isEmpty: function () {
+		return !this._latlngs.length || !this._latlngs[0].length;
+	},
+
 	getCenter: function () {
 		var i, j, p1, p2, f, area, x, y, center,
 		    points = this._rings[0],

src/layer/vector/Polyline.js

@@ -25,6 +25,10 @@ L.Polyline = L.Path.extend({
 		return this.redraw();
 	},
 
+	isEmpty: function () {
+		return !this._latlngs.length;
+	},
+
 	closestLayerPoint: function (p) {
 		var minDistance = Infinity,
 		    minPoint = null,