Check All , UnCheck All - AngularJs

Code to check and uncheck all using angularjs

HTML

<script src="//cdn.jsdelivr.net/underscorejs/1.5.1/underscore-min.js"></script>
<div>
    <ul ng-controller="checkboxController">
        <li>Check All
            <input type="checkbox" ng-model="selectedAll" ng-click="checkAll()" ng-checked="allSelected()"/>
        </li>
        <li ng-repeat="item in Items">
            <label>{{item.Name}}
                <input type="checkbox" ng-model="item.Selected" ng-change="checkAllChange()"/>
            </label>
            
        </li>
    </ul>
</div>

JavaScript

angular.module("CheckAllModule", [])
    .controller("checkboxController", function checkboxController($scope) {

    $scope.Items = [{
        Name: "Item one"
    }, {
        Name: "Item two"
    }, {
        Name: "Item three"
    }];
    $scope.checkAll = function () {
        if ($scope.selectedAll) {
            $scope.selectedAll = true;
        } else {
            $scope.selectedAll = false;
        }
        angular.forEach($scope.Items, function (item) {
            item.Selected = $scope.selectedAll;
        });
    };
        
     $scope.allSelected = function () {
          var allSelect = _.reduce($scope.Items, function (memo, todo) {
              return memo + (todo.Selected ? 1 : 0);
            }, 0);
          return (allSelect === $scope.Items.length);
      };

});