issue #123, formatted date when ngModel changes

Author: allenhwkim

app/directive-test.component.ts

@@ -34,6 +34,7 @@ var templateStr = `
           date-only="true"/>
         date2: {{date2}}
       </ng2-utils-2>
+      <a href="javascript:void(0)" (click)="myDate=defaultValue">set myDate</a><br/>
       <pre>{{templateStr | htmlCode:'ng2-utils-2'}}</pre>
     </fieldset>
      

package.json

@@ -60,7 +60,7 @@
     "typescript": "2.0.10",
     "webpack": "^1.13.3",
     "webpack-dev-server": "^1.16.2",
-    "webtest": "^0.2.13",
+    "webtest": "^0.3.6",
     "zone.js": "^0.6.21"
   }
 }

src/ng2-datetime-picker.directive.ts

@@ -152,7 +152,10 @@ export class Ng2DatetimePickerDirective implements OnInit, OnChanges {
     let date;
     if(changes && changes['ngModel']) {
       date = changes['ngModel'].currentValue;
-    } 
+      if (date && typeof date !== 'string') {
+        date.toString = () => Ng2Datetime.formatDate(date, this.dateFormat, this.dateOnly);
+      }
+    }
 
     this.setInputElDateValue(date);
     this.updateDatepicker();