how to reset variable after selecting?

Question

I'm building a project with angular and PHP. I have a "select" option which I can choose and it shows me all the "categories" I need and I need to select one. Then it can calculate the quantity of "products" when I pick a "category", but when I pick another "category" the total is no reset to 0 to count again it just counts more. Can someone please help?

this is my code:

Html:

     <select ng-model="stockReport.selectedOption" 
ng-change="computeTotal()" ng-options = "item.category_name for item in stockReport |
            unique:'category_name'">
    
            <option value="">בחר קטגוריה</option>
            </select>



 <div class="table-responsive">
 <table class="customer-list table table-striped" >
            <thead>
                 <tr >
                     <th class="Column-Header">קטגוריה</th>
                    <th class="Column-Header">קוד מוצר</th>
                     <th class="Column-Header">שם מוצר</th>
                     <th class="Column-Header">תיאור מוצר</th>
                     <th class="Column-Header">כמות במלאי</th>
                 </tr>
             </thead>
             <tbody>
                 <tr ng-repeat="item in stockReport" ng-if = "item.category_name == stockReport.selectedOption.category_name"
                  ng-init="setTotals(item)">
                     <td>{{item.category_name}}</td>
                     <td>{{item.stock_id}}</td>
                     <td>{{item.product_name}}</td>
                     <td>{{item.description}}</td>
                     <td>{{item.quantity}}</td>
                 </tr>
             </tbody>
             <tfoot>

                 <tr class="bg-warning">
                     <td><font size="6">סך הכל מוצרים במלאי:</font></td>
                     <td><font size="6">{{total}}</font></td>
                     <td></td>
                 </tr>
             </tfoot>
         </table>


 </div>

Controller function that calculate:

  $scope.total = 0;
      $scope.setTotals = function(item){
              // $scope.total = 0;
            if (item){
      
      
                 $scope.total += parseInt(item.quantity);
                 console.log($scope.total);
                 return $scope.total;
      
      
            }
      
        }

Answer 1

Seems like you want the sum of all the quantity of the table entry. Then you need to change the HTML code also

HTML:

<tbody>
             <tr ng-repeat="item in stockReport" ng-if = "item.category_name == stockReport.selectedOption.category_name"
              ng-init="setTotals(stockReport)">
                 <td>{{item.category_name}}</td>
                 <td>{{item.stock_id}}</td>
                 <td>{{item.product_name}}</td>
                 <td>{{item.description}}</td>
                 <td>{{item.quantity}}</td>
             </tr>
         </tbody>

OR

<select ng-options="......" ng-change="setTotals(stockReport)"></select> //this is better option and remove ng-init

JS:

$scope.setTotals = function(totalItem){
    $scope.total = 0;
     for(var item in totalItem){
       if (totalItem[item] && (totalItem[item].category_name == $scope.stockReport.selectedOption.category_name)){
         $scope.total += parseInt(totalItem[item].quantity);
         console.log($scope.total);
         return $scope.total;
       }
    }

}