Fixed issue with binding when binding to a falsy object (also added types.isNullOrundefined function).

camera/camera.android.ts

@@ -2,6 +2,7 @@
 import appModule = require("application");
 import fileSystem = require("file-system");
 import utils = require("utils/utils");
+import types = require("utils/types");
 import definition = require("camera");
 import common = require("./camera-common");
 
@@ -14,7 +15,7 @@ export var takePicture = function (options?: definition.CameraOptions): Promise<
             if (options) {
                 var reqWidth = options.width ? options.width * density : 0;
                 var reqHeight = options.height ? options.height * density : reqWidth;
-                var shouldKeepAspectRatio = (options.keepAspectRatio === null || options.keepAspectRatio === undefined) ? true : options.keepAspectRatio;
+                var shouldKeepAspectRatio = types.isNullOrUndefined(options.keepAspectRatio) ? true : options.keepAspectRatio;
             }
             var takePictureIntent = new android.content.Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
             var dateStamp = createDateTimeStamp();

camera/camera.ios.ts

@@ -2,6 +2,7 @@
 import frame = require("ui/frame");
 import definition = require("camera");
 import common = require("./camera-common");
+import types = require("utils/types");
 
 class UIImagePickerControllerDelegateImpl extends NSObject implements UIImagePickerControllerDelegate {
     public static ObjCProtocols = [UIImagePickerControllerDelegate];
@@ -26,7 +27,7 @@ class UIImagePickerControllerDelegateImpl extends NSObject implements UIImagePic
         if (options) {
             this._width = options.width;
             this._height = options.height;
-            this._keepAspectRatio = (options.keepAspectRatio === null || options.keepAspectRatio === undefined) ? true : options.keepAspectRatio;
+            this._keepAspectRatio = types.isNullOrUndefined(options.keepAspectRatio) ? true : options.keepAspectRatio;
         }
         return this;
     }
@@ -76,7 +77,7 @@ export var takePicture = function (options?: definition.CameraOptions): Promise<
         if (options) {
             reqWidth = options.width || 0;
             reqHeight = options.height || reqWidth;
-            keepAspectRatio = (options.keepAspectRatio === null || options.keepAspectRatio === undefined) ? true : options.keepAspectRatio;
+            keepAspectRatio = types.isNullOrUndefined(options.keepAspectRatio) ? true : options.keepAspectRatio;
         }
         if (reqWidth && reqHeight) {
             listener = UIImagePickerControllerDelegateImpl.new().initWithCallbackAndOptions(resolve, { width: reqWidth, height: reqHeight, keepAspectRatio: keepAspectRatio });

ui/core/bindable.ts

@@ -44,7 +44,7 @@ export class Bindable extends dependencyObservable.DependencyObservable implemen
         if (!bindingSource) {
             bindingSource = this.bindingContext;
         }
-        if (bindingSource) {
+        if (!types.isNullOrUndefined(bindingSource)) {
             binding.bind(bindingSource);
         }
     }
@@ -109,7 +109,7 @@ export class Bindable extends dependencyObservable.DependencyObservable implemen
                 " targetProperty: " + binding.options.targetProperty +
                 " to the changed context: " + newValue, trace.categories.Binding);
             binding.unbind();
-            if (newValue) {
+            if (!types.isNullOrUndefined(newValue)) {
                 binding.bind(newValue);
             }
         }
@@ -134,7 +134,7 @@ export class Binding {
     }
 
     public bind(obj: Object) {
-        if (!obj) {
+        if (types.isNullOrUndefined(obj)) {
             throw new Error("Expected valid object reference as a source in the Binding.bind method.");
         }
 
@@ -344,7 +344,7 @@ export class Binding {
                 currentObject = currentObject[properties[i]];
             }
 
-            if (currentObject !== undefined && currentObject !== null) {
+            if (!types.isNullOrUndefined(currentObject)) {
                 options = {
                     instance: new WeakRef(currentObject),
                     property: properties[properties.length - 1]

ui/tab-view/tab-view.android.ts

@@ -4,6 +4,7 @@ import dependencyObservable = require("ui/core/dependency-observable");
 import view = require("ui/core/view");
 import trace = require("trace");
 import imageSource = require("image-source");
+import types = require("utils/types");
 
 var VIEWS_STATES = "_viewStates";
 
@@ -436,7 +437,7 @@ export class TabView extends common.TabView {
     }
 
     private _setNativeSelectedIndex(index: number) {
-        if (index === undefined || index === null) {
+        if (types.isNullOrUndefined(index)) {
             return;
         }
 

ui/tab-view/tab-view.ios.ts

@@ -6,6 +6,7 @@ import trace = require("trace");
 import utils = require("utils/utils");
 import view = require("ui/core/view");
 import imageSource = require("image-source");
+import types = require("utils/types");
 
 // merge the exports of the common file with the exports of this file
 declare var exports;
@@ -206,7 +207,7 @@ export class TabView extends common.TabView {
 
         var newIndex = data.newValue;
         trace.write("TabView._onSelectedIndexPropertyChangedSetNativeValue(" + newIndex + ")", trace.categories.Debug);
-        if (newIndex === undefined || newIndex === null) {
+        if (types.isNullOrUndefined(newIndex)) {
             return;
         }
 

utils/types.d.ts

@@ -28,12 +28,19 @@
     export function isUndefined(value: any): boolean;
 
     /**
-     * A function that checks if something is defined (not null and not undefined).
+     * A function that checks if something is defined (not undefined).
      * @param value The value which will be checked.
      * Returns true if value is defined.
      */
     export function isDefined(value: any): boolean;
 
+    /**
+     * A function that checks if something is not defined (null or undefined).
+     * @param value The value which will be checked.
+     * Returns true if value is null or undefined.
+     */
+    export function isNullOrUndefined(value: any): boolean;
+
     /**
      * A function that checks if something is a valid function.
      * @param value The value which will be checked.

utils/types.ts

@@ -21,6 +21,10 @@ export function isDefined(value: any): boolean {
     return typeof value !== "undefined";
 }
 
+export function isNullOrUndefined(value: any): boolean {
+    return (typeof value === "undefined") || (value === null);
+}
+
 export function verifyCallback(value: any) {
     if (value && !isFunction(value)) {
         throw new TypeError("Callback must be a valid function.");