I am using angularjs in my project. I am getting date string from back end. Date string can be any string which may be a date or may not be date. When I set the date string to `ng-model` if it's a date string then it's working fine else it throws an exception 

```
Error: [ngModel:datefmt] http://errors.angularjs.org/1.4.3/ngModel/datefmt?p0=asdfdaf
    at Error (native)
    at http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:6:416
    at Array.<anonymous> (http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:167:250)
    at Object.<anonymous> (http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:264:75)
    at n.$get.n.$digest (http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:132:124)
    at n.$get.n.$apply (http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:135:269)
    at http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:19:437
    at Object.e [as invoke] (http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:39:156)
    at d (http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:19:358)
    at Ac (http://ajax.googleapis.com/ajax/libs/angularjs/1.4.3/angular.min.js:20:151)

```

I don't know how to handle this exception. I am thinking about writing a method like `isDate(dateString)` but I don't know what should I write inside it cause date string can be any string in any format. Please help, I have created [plunkr here](http://plnkr.co/edit/yBnzg9H1ZQlAx7YwRrn2?p=preview)