Better tracing (logging) of run-time errors.

apps/tests/ui-test.ts

@@ -47,7 +47,6 @@ export class UITest<T extends View> implements trace.TraceWriter {
         };
 
         trace.addWriter(this);
-        trace.enable();
         navHelper.navigate(pageFactory);
     }
 

apps/tests/ui/bindable-tests.ts

@@ -14,6 +14,7 @@ import labelModule = require("ui/label");
 import textFieldModule = require("ui/text-field");
 import fs = require("file-system");
 import appModule = require("application");
+import trace = require("trace");
 
 // <snippet module="ui/core/bindable" title="bindable">
 // For information and examples how to use bindings please refer to special [**Data binding**](../../../../bindings.md) topic. 
@@ -693,6 +694,29 @@ export function test_NestedPropertiesBinding() {
     TKUnit.assertEqual(target1.get("targetProperty"), newExpectedValue);
 }
 
+export function test_WrongNestedPropertiesBinding() {
+    var expectedValue = "Default Text";
+    var viewModel = new observable.Observable();
+    viewModel.set("activity", new Activity(expectedValue, "Default First Name", "Default Last Name"));
+    let errorMessage;
+    let traceWriter = {
+        write: function (message, category, type?) {
+            errorMessage = message;
+        }
+    }
+    trace.addWriter(traceWriter);
+
+    var target1 = new bindable.Bindable();
+    target1.bind({
+        sourceProperty: "activity.",
+        targetProperty: "targetProperty",
+        twoWay: true
+    }, viewModel);
+
+    TKUnit.assertNotEqual(errorMessage, undefined);
+    trace.removeWriter(traceWriter);
+}
+
 export function test_NestedPropertiesBindingTwoTargets() {
     var expectedText = "Default Text";
     var expectedFirstName = "Default First Name";

trace/trace.ts

@@ -48,6 +48,14 @@ export function addCategories(categories: string) {
 }
 
 export function write(message: any, category: string, type?: number) {
+    // print error no matter what
+    var i;
+    if (type === messageType.error) {
+        for (i = 0; i < _writers.length; i++) {
+            _writers[i].write(message, category, type);
+        }
+    }
+    
     if (!_enabled) {
         return;
     }
@@ -56,7 +64,7 @@ export function write(message: any, category: string, type?: number) {
         return;
     }
 
-    var i;
+    
     for (i = 0; i < _writers.length; i++) {
         _writers[i].write(message, category, type);
     }
@@ -113,6 +121,7 @@ export module categories {
     export var Navigation = "Navigation";
     export var Test = "Test";
     export var Binding = "Binding";
+    export var BindingError = "BindingError";
     export var Error = "Error";
     export var Animation = "Animation";
     export var Transition = "Transition";

ui/core/bindable.ts

@@ -252,22 +252,25 @@ export class Binding {
         var currentObjectChanged = false;
         for (i = 0; i < propsArrayLength; i++) {
             objProp = propsArray[i];
-            if (propsArray[i] === bc.bindingValueKey) {
+            if (objProp === bc.bindingValueKey) {
                 currentObjectChanged = true;
             }
-            if (propsArray[i] === bc.parentValueKey || propsArray[i].indexOf(bc.parentsValueKey) === 0) {
+            if (objProp === bc.parentValueKey || objProp.indexOf(bc.parentsValueKey) === 0) {
-                var parentView = this.getParentView(this.target.get(), propsArray[i]).view;
+                var parentView = this.getParentView(this.target.get(), objProp).view;
                 if (parentView) {
                     currentObject = parentView.bindingContext;
-                }
+                } else {
-                else {
                     var targetInstance = this.target.get();
                     targetInstance.off(viewModule.View.loadedEvent, this.loadedHandlerVisualTreeBinding, this);
                     targetInstance.on(viewModule.View.loadedEvent, this.loadedHandlerVisualTreeBinding, this);
                 }
                 currentObjectChanged = true;
             }
+            if (currentObject) {
                 result.push({ instance: currentObject, property: objProp });
+            } else {
+                break;
+            }
             // do not need to dive into last object property getter on binding stage will handle it
             if (!currentObjectChanged && (i < propsArrayLength - 1)) {
                 currentObject = currentObject ? currentObject[propsArray[i]] : null;
@@ -285,7 +288,7 @@ export class Binding {
             for (i = 0; i < objectsAndPropertiesLength; i++) {
                 var prop = objectsAndProperties[i].property;
                 var currentObject = objectsAndProperties[i].instance;
-                if (currentObject && !this.propertyChangeListeners[prop] && currentObject instanceof observable.Observable) {
+                  if (!this.propertyChangeListeners[prop] && currentObject instanceof observable.Observable) {
                     weakEvents.addWeakEventListener(
                         currentObject,
                         observable.Observable.propertyChangeEvent,
@@ -504,13 +507,13 @@ export class Binding {
             var sourceOptionsInstance = this.sourceOptions.instance.get();
             if (this.sourceOptions.property === bc.bindingValueKey) {
                 value = sourceOptionsInstance;
-            }
+            } else if ((sourceOptionsInstance instanceof observable.Observable) && (this.sourceOptions.property && this.sourceOptions.property !== "")) {
-            else if (sourceOptionsInstance instanceof observable.Observable) {
                 value = sourceOptionsInstance.get(this.sourceOptions.property);
-            }
+            } else if (sourceOptionsInstance && this.sourceOptions.property && this.sourceOptions.property !== "" &&
-            else if (sourceOptionsInstance && this.sourceOptions.property &&
                 this.sourceOptions.property in sourceOptionsInstance) {
                 value = sourceOptionsInstance[this.sourceOptions.property];
+            } else {
+                trace.write("Property: '" + this.sourceOptions.property + "' is invalid or does not exist. SourceProperty: '" + this.options.sourceProperty + "'", trace.categories.Binding, trace.messageType.error);
             }
         }
         return value;
@@ -564,8 +567,7 @@ export class Binding {
                     result = result.parent;
                     indexAsInt--;
                 }
-            }
+            } else if (types.isString(index)) {
-            else if (types.isString(index)) {
                 while (result && result.typeName !== index) {
                     result = result.parent;
                 }
@@ -580,13 +582,11 @@ export class Binding {
         if (objectsAndProperties.length > 0) {
             var resolvedObj = objectsAndProperties[objectsAndProperties.length - 1].instance;
             var prop = objectsAndProperties[objectsAndProperties.length - 1].property;
-            if (resolvedObj) {
                 return {
                     instance: new WeakRef(resolvedObj),
                     property: prop
             }
         }
-        }
         return null;
     }
 

utils/utils.android.ts

@@ -266,8 +266,9 @@ export function openUrl(location: string): boolean {
 
         context.startActivity(intent);
     } catch (e) {
+        ensureTrace();
         // We Don't do anything with an error.  We just output it
-        console.error("Error in OpenURL", e);
+        trace.write("Error in OpenURL", trace.categories.Error, trace.messageType.error);
         return false;
     }
     return true;

utils/utils.ios.ts

@@ -4,9 +4,17 @@ import common = require("./utils-common");
 import {Color} from "color";
 import enums = require("ui/enums");
 import * as fsModule from "file-system";
+import * as traceModule from "trace";
 
 global.moduleMerge(common, exports);
 
+var trace: typeof traceModule;
+function ensureTrace() {
+    if (!trace) {
+        trace = require("trace");
+    }
+}
+
 function isOrientationLandscape(orientation: number) {
     return orientation === UIDeviceOrientation.UIDeviceOrientationLandscapeLeft || orientation === UIDeviceOrientation.UIDeviceOrientationLandscapeRight;
 }
@@ -234,7 +242,8 @@ export module ios {
             return controller.presentPreviewAnimated(true);
         }
         catch (e) {
-            console.error("Error in openFile", e);
+            ensureTrace();
+            trace.write("Error in openFile", trace.categories.Error, trace.messageType.error);
         }
         return false;
     }
@@ -252,8 +261,9 @@ export function openUrl(location: string): boolean {
         }
     }
     catch (e) {
+        ensureTrace();
         // We Don't do anything with an error.  We just output it
-        console.error("Error in OpenURL", e);
+        trace.write("Error in OpenURL", trace.categories.Error, trace.messageType.error);
     }
     return false;
 }