better implementation, more tests

spec/suites/core/EventsSpec.js

@@ -246,12 +246,12 @@ describe('Events', function() {
 		});
 	});
 
-	describe('#once', function(){
+	describe('#once', function() {
 		it('removes event listeners after first fire', function() {
 			var obj = new Klass(),
 				spy = new sinon.spy();
 
-			obj.once('test', spy);
+			obj.once('test', spy, obj);
 			obj.fire('test');
 
 			expect(spy.called).to.be(true);
@@ -269,7 +269,7 @@ describe('Events', function() {
 			obj.once({
 				test: spy,
 				otherTest: otherSpy
-			});
+			}, obj);
 
 			obj.fire('test');
 			obj.fire('otherTest');
@@ -284,7 +284,7 @@ describe('Events', function() {
 			expect(otherSpy.callCount).to.be.lessThan(2);
 		});
 
-		it('only removes the fired event handler', function(){
+		it('only removes the fired event handler', function() {
 			var obj = new Klass(),
 				spy = new sinon.spy(),
 				otherSpy = new sinon.spy();
@@ -306,5 +306,66 @@ describe('Events', function() {
 			expect(spy.callCount).to.be.lessThan(2);
 			expect(otherSpy.callCount).to.be.lessThan(2);
 		});
+
+		it('can be passed multiple types', function() {
+			var obj = new Klass(),
+				spy = new sinon.spy(),
+				otherSpy = new sinon.spy();
+
+			obj.once('test otherTest', spy, obj);
+			obj.fire('otherTest');
+
+			expect(spy.called).to.be(true);
+
+			obj.fire('test');
+
+			expect(spy.callCount).to.be.lessThan(2);
+		});
+
+		it('provides event object to listeners and executes with the correct context', function() {
+			var obj = new Klass(),
+				obj2 = new Klass(),
+				obj3 = new Klass(),
+				obj4 = new Klass(),
+				foo = new Klass();
+
+			function listener1(e) {
+				expect(e.type).to.eql('test');
+				expect(e.target).to.eql(obj);
+				expect(this).to.eql(obj);
+				expect(e.baz).to.eql(1);
+			}
+
+			function listener2(e) {
+				expect(e.type).to.eql('test');
+				expect(e.target).to.eql(obj2);
+				expect(this).to.eql(foo);
+				expect(e.baz).to.eql(2);
+			}
+
+			function listener3(e) {
+				expect(e.type).to.eql('test');
+				expect(e.target).to.eql(obj3);
+				expect(this).to.eql(obj3);
+				expect(e.baz).to.eql(3);
+			}
+
+			function listener4(e) {
+				expect(e.type).to.eql('test');
+				expect(e.target).to.eql(obj4);
+				expect(this).to.eql(foo);
+				expect(e.baz).to.eql(4);
+			}
+
+			obj.once('test', listener1);
+			obj2.once('test', listener2, foo);
+			obj3.once({ test: listener3 });
+			obj4.once({ test: listener4 }, foo);
+
+			obj.fireEvent('test', {baz: 1});
+			obj2.fireEvent('test', {baz: 2});
+			obj3.fireEvent('test', {baz: 3});
+			obj4.fireEvent('test', {baz: 4});
+		});
 	});
 });

src/core/Events.js

@@ -115,10 +115,7 @@ L.Mixin.Events = {
 			return this;
 		}
 
-		var event = L.Util.extend({}, data, {
-			type: type,
-			target: this
-		});
+		var event = L.Util.extend({}, data, { type: type, target: this });
 
 		var listeners, i, len, eventsObj, contextId;
 
@@ -151,26 +148,34 @@ L.Mixin.Events = {
 	},
 
 	once: function(types, fn, context) {
-		handlerFor = function(fn, type, context) {
-			var handler = function() {
-				this.removeEventListener(type, fn, context);
-				this.removeEventListener(type, handler, context);
+		var once = function(fn) {
+			var done = false;
+			return function() {
+				if (done) return;
+				fn.apply(this, arguments);
+				fn = null;
+				done = true;
 			}
-			return handler;
 		}
 
+		var handlerFor = L.bind(function(type, fn, context) {
+			var handler = once(function() {
+				this.removeEventListener(types, handler);
+				fn.apply(context || this, arguments);
+			});
+			return handler;
+		}, this);
+
 		if (typeof types === 'object') {
 			for (type in types) {
 				if (types.hasOwnProperty(type)) {
-					this.addEventListener(type, types[type], fn);
-					this.addEventListener(type, handlerFor(types[type], type, fn), fn);
+					this.addEventListener(type, handlerFor(type, types[type], fn), fn);
 				}
 			}
 			return this;
 		}
 
-		this.addEventListener(types, fn, context);
-		return this.addEventListener(types, handlerFor(fn, types, context), context);
+		return this.addEventListener(types, handlerFor(types,fn,context), context);
 	}
 };