title: strict mode filter in angularjs
body: <p>i just wanted to implement strict filter as a option when user inputs a string with prefix "!" otherwise normal filter</p>
  
  <p>this is what i have done
  <a href="http://plnkr.co/edit/QaroPDzQxeLNjt4vZgRb?p=preview" rel="nofollow">http://plnkr.co/edit/QaroPDzQxeLNjt4vZgRb?p=preview</a></p>
  
  <p>script:</p>
  
  <pre><code>angular.module('inputExample', [])
     .controller('ExampleController', ['$scope', function($scope) {
       $scope.filter = { friends : [{name:'John', phone:'555-1276'},
                           {name:'Mary', phone:'800-BIG-MARY'},
                           {name:'Mike', phone:'555-4321'},
                           {name:'Adam', phone:'555-5678'},
                           {name:'Julie', phone:'555-8765'},
                           {name:'Juliette', phone:'555-5678'}] };
       $scope.opt = {
          strict : false,
          val : ''
       };
     }]);
  </code></pre>
  
  <p>html :</p>
  
  <pre><code>&lt;form name="testForm" ng-controller="ExampleController"&gt;
    &lt;input ng-model="opt.val"  placeholder="prefix ! for strict" ng-value="opt.val.substring(1)" class="my-input" /&gt;
    &lt;input type="checkbox" style="display:none;" ng-model="opt.strict" ng-bind="opt.strict" ng-checked="opt.val.chatAt(0)==='!'" class="my-input" /&gt;
    &lt;table id="searchObjResults"&gt;
    &lt;tr&gt;&lt;th&gt;Name&lt;/th&gt;&lt;th&gt;Phone&lt;/th&gt;&lt;/tr&gt;
    &lt;tr ng-repeat="friendObj in filter.friends | filter:opt.val:opt.strict"&gt;
      &lt;td&gt;{{friendObj.name}}&lt;/td&gt;
      &lt;td&gt;{{friendObj.phone}}&lt;/td&gt;
    &lt;/tr&gt;
  &lt;/table&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>But its not working.</p>
  
  <p>Why?</p>
  
  <p>And how do i make it work?</p>