[javascript] AngularJs - ng-model in a SELECT

JSfiddle

Problem:

I have a SELECT-element in my page, which is filled in with an ng-repeat. It also has a ng-model which has a default value.

When I change the value, the ng-model adapts, that's ok. But the dropdown-list shows an empty slot at launch, where it should have the item with the default value selected instead.

Code

<div ng-app ng-controller="myCtrl">
    <select class="form-control" ng-change="unitChanged()" ng-model="data.unit">
         <option ng-repeat="item in units" ng-value="item.id">{{item.label}}</option>
    </select>
</div>

With JS:

function myCtrl ($scope) {
    $scope.units = [
        {'id': 10, 'label': 'test1'},
        {'id': 27, 'label': 'test2'},
        {'id': 39, 'label': 'test3'},
    ]

        $scope.data = {
        'id': 1,
        'unit': 27
        }

};

However, ngOptions provides some benefits such as reducing memory and increasing speed by not creating a new scope for each repeated instance. angular docs

Alternative solution is use ng-init directive. You can specify function that will be initialize your default data.

$scope.init = function(){
            angular.forEach($scope.units, function(item){
                if(item.id === $scope.data.unit){
                    $scope.data.unit = item;
                }
            });
        } 

See jsfiddle

You can also put the item with the default value selected out of the ng-repeat like follow :

<div ng-app="app" ng-controller="myCtrl">
    <select class="form-control" ng-change="unitChanged()" ng-model="data.unit">
        <option value="yourDefaultValue">Default one</option>
        <option ng-selected="data.unit == item.id" ng-repeat="item in units" ng-value="item.id">{{item.label}}</option>
    </select>
</div>

and don't forget the value atribute if you leave it blank you will have the same issue.

Select's default value should be one of its value in the list. In order to load the select with default value you can use ng-options. A scope variable need to be set in the controller and that variable is assigned as ng-model in HTML's select tag.

View this plunker for any references:

http://embed.plnkr.co/hQiYqaQXrtpxQ96gcZhq/preview

try the following code :

In your controller :

 function myCtrl ($scope) {
      $scope.units = [
         {'id': 10, 'label': 'test1'},
         {'id': 27, 'label': 'test2'},
         {'id': 39, 'label': 'test3'},
      ];

   $scope.data= $scope.units[0]; // Set by default the value "test1"
 };

In your page :

 <select ng-model="data" ng-options="opt as opt.label for opt in units ">
                </select>

Working Fiddle

You dont need to define option tags, you can do this using the ngOptions directive: https://docs.angularjs.org/api/ng/directive/ngOptions

<select class="form-control" ng-change="unitChanged()" ng-model="data.unit" ng-options="unit.id as unit.label for unit in units"></select>