Angular: Empty Fiddle

http://angularjs.org/

HTML

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.14/angular.min.js"></script>
<div  ng-controller="MyCtrl">
    <input type="text" ng-model="minPotatoes" ng-keyup="onKeyup($event, minPotatoes)" />
     <input type="text" ng-model="maxPotatoes" ng-keyup="onKeyup($event, maxPotatoes)" />
</div>

JavaScript

var myApp = angular.module('myApp',[]);
    

function MyCtrl($scope) {
    $scope.onKeyup = function (evt, val) {
        if(evt.keyCode === 40) {
            val -= 1
            console.log("decrementing val", val)
        } else if (evt.keyCode === 38) {
            val += 1
            console.log("incrementing val", val)
        }
    }
    $scope.minPotatoes = 2;
    $scope.maxPotatoes = 10;
}