Merge pull request #1376 from moonlite/zoomlevelschange-event

Zoomlevelschange event

spec/suites/map/MapSpec.js

@@ -1,10 +1,14 @@
 describe("Map", function () {
+	var map,
+		spy;
+	beforeEach(function () {
+		map = L.map(document.createElement('div'));
+		spy = jasmine.createSpy();
+	});
+
 	describe("#whenReady", function () {
 		describe("when the map has not yet been loaded", function () {
 			it("calls the callback when the map is loaded", function () {
-				var map = L.map(document.createElement('div')),
-					spy = jasmine.createSpy();
-
 				map.whenReady(spy);
 				expect(spy).not.toHaveBeenCalled();
 
@@ -15,9 +19,6 @@ describe("Map", function () {
 
 		describe("when the map has already been loaded", function () {
 			it("calls the callback immediately", function () {
-				var map = L.map(document.createElement('div')),
-					spy = jasmine.createSpy();
-
 				map.setView([0, 0], 1);
 				map.whenReady(spy);
 
@@ -29,9 +30,6 @@ describe("Map", function () {
 	describe("#getBounds", function () {
 		it("is safe to call from within a moveend callback during initial "
 		   + "load (#1027)", function () {
-			var c = document.createElement('div'),
-				map = L.map(c);
-
 			map.on("moveend", function () {
 			  map.getBounds();
 			});
@@ -51,4 +49,90 @@ describe("Map", function () {
 			   expect(map.getMaxZoom()).toBe(10);
 		   });
 	});
+
+	describe("#addLayer", function () {
+		describe("When the first layer is added to a map", function () {
+			it("should fire a zoomlevelschange event", function () {
+				map.on("zoomlevelschange", spy);
+				expect(spy).not.toHaveBeenCalled();
+				L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 10 }).addTo(map);
+				expect(spy).toHaveBeenCalled();
+			});
+		});
+		describe("when a new layer with greater zoomlevel coverage than the current layer is added to a map", function () {
+			it("Should fire a zoomlevelschange event ",
+			   function () {
+				   L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 10 }).addTo(map);
+				   map.on("zoomlevelschange", spy);
+				   expect(spy).not.toHaveBeenCalled();
+				   L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 15 }).addTo(map);
+				   expect(spy).toHaveBeenCalled();
+			   });
+		});
+		describe("when a new layer with the same or lower zoomlevel coverage as the current layer is added to a map", function () {
+			it("Shouldn't fire a zoomlevelschange event ",
+			   function () {
+				   L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 10 }).addTo(map);
+				   map.on("zoomlevelschange", spy);
+				   expect(spy).not.toHaveBeenCalled();
+				   L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 10 }).addTo(map);
+				   expect(spy).not.toHaveBeenCalled();
+			   	   L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 5 }).addTo(map);
+				   expect(spy).not.toHaveBeenCalled();
+
+			   });
+		});
+
+	});
+	describe("#removeLayer", function () {
+		describe("when the last tile layer on a map is removed", function () {
+			it("should fire a zoomlevelschange event ", function () {
+				   map.whenReady(function(){
+					   var tl = L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 10 })
+							   .addTo(map);
+
+					   map.on("zoomlevelschange", spy);
+					   expect(spy).not.toHaveBeenCalled();
+					   map.removeLayer(tl);
+					   expect(spy).toHaveBeenCalled();
+				   });
+			   });
+		});
+		describe("when a tile layer is removed from a map and it had greater zoom level coverage than the remainding layer", function () {
+			it("should fire a zoomlevelschange event ", function () {
+				   map.whenReady(function(){
+					   var tl = L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 10 })
+							   .addTo(map),
+						   t2 = L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 15 })
+							   .addTo(map);
+
+					   map.on("zoomlevelschange", spy);
+					   expect(spy).not.toHaveBeenCalled();
+					   map.removeLayer(t2);
+					   expect(spy).toHaveBeenCalled();
+				   });
+			});
+		});
+		describe("when a tile layer is removed from a map it and it had lesser or the sa,e zoom level coverage as the remainding layer(s)", function () {
+			it("shouldn't fire a zoomlevelschange event ", function () {
+				map.whenReady(function(){
+					var tl = L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 10 })
+							.addTo(map),
+						t2 = L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 10 })
+							.addTo(map),
+						t3 = L.tileLayer("{z}{x}{y}", { minZoom:0, maxZoom: 5 })
+							.addTo(map);
+
+					map.on("zoomlevelschange", spy);
+					expect(spy).not.toHaveBeenCalled();
+					map.removeLayer(t2);
+					expect(spy).not.toHaveBeenCalled();
+					map.removeLayer(t3);
+					expect(spy).not.toHaveBeenCalled();
+
+				});
+			});
+		});
+
+	});
 });

src/map/Map.js

@@ -532,10 +532,15 @@ L.Map = L.Class.extend({
 		L.DomUtil.setPosition(this._mapPane, this._getMapPanePos().subtract(offset));
 	},
 
+	_getZoomSpan: function () {
+		return this.getMaxZoom() - this.getMinZoom();
+	},
+
 	_updateZoomLevels: function () {
 		var i,
 			minZoom = Infinity,
-			maxZoom = -Infinity;
+			maxZoom = -Infinity,
+			oldZoomSpan = this._getZoomSpan();
 
 		for (i in this._zoomBoundLayers) {
 			if (this._zoomBoundLayers.hasOwnProperty(i)) {
@@ -555,6 +560,10 @@ L.Map = L.Class.extend({
 			this._layersMaxZoom = maxZoom;
 			this._layersMinZoom = minZoom;
 		}
+
+		if (oldZoomSpan !== this._getZoomSpan()) {
+			this.fire("zoomlevelschange");
+		}
 	},
 
 	// map events