AngularJS Example:

HTML

<div ng-controller="FirstCtrl">
    <div ng-repeat="purchasedItem in purchasedItems" class="row item_summary">{{purchasedItem}}
        <div ng-controller="numpadCtrl as numpad" class="numpad">
            <!-- edited for brevity -->
            <input type="button" class="btn btn-sm" value="enter" data-item-id='{{purchasedItem.code}}' ng-click="numpad.flushNumber(purchasedItem.code)"></input>
        </div>
    </div>
</div>

JavaScript

function FirstCtrl($scope) {
    $scope.purchasedItems = [{
        code: 'hello'
    }, {
        code: 'world'
    }];
}

function numpadCtrl($scope) {
    this.flushNumber = function (code) {
        console.log(code);
    }
}