Handle beforechange events for bound properties

test/spec/ol/object.test.js

@@ -215,7 +215,7 @@ describe('ol.Object', function() {
 
       o2.set('k', 2);
       expect(beforeListener.calledOnce).to.be(true);
-      var args = listener2.firstCall.args;
+      var args = beforeListener.firstCall.args;
       expect(args).to.have.length(1);
       var event = args[0];
       expect(event.key).to.be('k');
@@ -223,6 +223,54 @@ describe('ol.Object', function() {
       expect(oldValue).to.be(1);
     });
 
+    it('relays beforechange events from bound objects', function() {
+      var target = new ol.Object({
+        foo: 'original value'
+      });
+      var object = new ol.Object();
+      object.bindTo('foo', target);
+
+      var oldValue;
+      var beforeListener = sinon.spy(function(event) {
+        oldValue = object.get(event.key);
+      });
+      object.on('beforechange', beforeListener);
+
+      target.set('foo', 'new value');
+      expect(beforeListener.calledOnce).to.be(true);
+      var args = beforeListener.firstCall.args;
+      expect(args).to.have.length(1);
+      var event = args[0];
+      expect(event.key).to.be('foo');
+
+      expect(oldValue).to.be('original value');
+      expect(object.get('foo')).to.be('new value');
+    });
+
+    it('relays beforechange events when bound with a new key', function() {
+      var target = new ol.Object({
+        foo: 'original value'
+      });
+      var object = new ol.Object();
+      object.bindTo('bar', target, 'foo');
+
+      var oldValue;
+      var beforeListener = sinon.spy(function(event) {
+        oldValue = object.get(event.key);
+      });
+      object.on('beforechange', beforeListener);
+
+      target.set('foo', 'new value');
+      expect(beforeListener.calledOnce).to.be(true);
+      var args = beforeListener.firstCall.args;
+      expect(args).to.have.length(1);
+      var event = args[0];
+      expect(event.key).to.be('bar');
+
+      expect(oldValue).to.be('original value');
+      expect(object.get('bar')).to.be('new value');
+    });
+
   });
 
   describe('bind', function() {
@@ -302,6 +350,59 @@ describe('ol.Object', function() {
       expect(o.get('k')).to.eql(1);
       expect(o2.get('k')).to.eql(2);
     });
+
+    it('stops relaying beforechange events', function() {
+      var target = new ol.Object({
+        foo: 'original value'
+      });
+      var object = new ol.Object();
+      object.bindTo('foo', target);
+
+      var listener = sinon.spy();
+      object.on('beforechange', listener);
+
+      target.set('foo', 'new value');
+      expect(listener.calledOnce).to.be(true);
+      var call = listener.firstCall;
+      expect(call.args).to.have.length(1);
+      expect(call.args[0].key).to.be('foo');
+
+      object.unbind('foo');
+      target.set('foo', 'another new value');
+      expect(listener.calledOnce).to.be(true);
+
+      expect(object.get('foo')).to.be('new value');
+    });
+
+    it('selectively stops relaying beforechange events', function() {
+      var target = new ol.Object({
+        foo: 'original foo',
+        bar: 'original bar'
+      });
+      var object = new ol.Object();
+      object.bindTo('foo', target);
+      object.bindTo('bar', target);
+
+      var listener = sinon.spy();
+      object.on('beforechange', listener);
+
+      target.set('foo', 'new foo');
+      expect(listener.calledOnce).to.be(true);
+
+      target.set('bar', 'new bar');
+      expect(listener.callCount).to.be(2);
+
+      object.unbind('foo');
+      target.set('foo', 'another new foo');
+      expect(listener.callCount).to.be(2);
+
+      target.set('bar', 'another new bar');
+      expect(listener.callCount).to.be(3);
+      var lastCall = listener.getCall(2);
+      expect(lastCall.args).to.have.length(1);
+      expect(lastCall.args[0].key).to.be('bar');
+    });
+
   });
 
   describe('unbindAll', function() {