Merge pull request #139 from NativeScript/set-observable-array-length-

missing setter for observable array added

apps/tests/observable-array-tests.ts

@@ -45,6 +45,21 @@ export var test_ObservableArray_shouldCreateArrayFromSpecifiedLength = function
     TKUnit.assert(array.length === 100, "ObservableArray should create array from specified length!");
 };
 
+export var test_ObservableArray_shouldBeAbleToSetLength = function () {
+    // <snippet module="data/observable-array" title="observable-array">
+    // ### Set ObservableArray length to new value.
+    // ``` JavaScript
+    var array = new observableArrayModule.ObservableArray(100);
+    // <hide>
+    TKUnit.assert(array.length === 100, "ObservableArray should create array from specified length!");
+    // </hide>
+    array.length = 50;
+    // ```
+    // </snippet>
+
+    TKUnit.assert(array.length === 50, "ObservableArray should respect new length!");
+};
+
 export var test_ObservableArray_getItemShouldReturnCorrectItem = function () {
     // <snippet module="data/observable-array" title="observable-array">
     // ### Get item at specified index using getItem(index) method.

data/observable-array/observable-array.ts

@@ -1,5 +1,6 @@
 import observable = require("data/observable");
 import observableArrayDef = require("data/observable-array");
+import types = require("utils/types");
 
 export class ChangeType implements observableArrayDef.ChangeType {
     static Add = "add";
@@ -66,6 +67,12 @@ export class ObservableArray<T> extends observable.Observable implements observa
     get length(): number {
         return this._array.length;
     }
+    set length(value: number) {
+        if (types.isNumber(value) && this._array && this._array.length !== value) {
+            this._array = this._array.slice(0, value);
+            this._notifyLengthChange();
+        }
+    }
 
     /**
      * Returns a string representation of an array.