Chapter 7: Optimizing using $watch deregistration

HTML

<script src="https://code.angularjs.org/1.3.2/angular.min.js"></script>
<div ng-app="myApp">
    <div ng-controller="Ctrl">
        <input ng-model="val" />
        <button ng-click="unwatch()">Unwatch</button>
        <br>
        aaa = {{val}}
        
    </div>
</div>

JavaScript

angular.module('myApp', [])
.controller('Ctrl', function ($scope, $log) {
    $scope.unwatch = $scope.$watch('val', function() {
        $log.log('entered watcher callback');
    });
});