Variable scope fails to update upon selection change

Question

Variable scope fails to update upon selection change

I'm currently setting up a select dropdown with an ng-options. The dropdown is appearing correctly on the HTML page, but for some reason, when I choose an option, the variable specified by ng-model is not updating in $scope.

This is the HTML code:

<select ng-model="selected_ingredient"
        ng-options="item as item.ingredient for item in available_ingredients"
        ng-change="selectIngredient()">
    <option value="">Add an ingredient...</option>
</select>

And this is the AngularJS code:

$scope.selectIngredient = function() {
    if ( $scope.debug > 0 ) {
        console.log( "Selected ingredient:" );
        console.log( $scope.selected_ingredient );
    }
};

When checking the console output after selecting a dropdown item (with $scope.debug set to 1), it shows:

Selected ingredient:
undefined

My goal is for $scope.selected_ingredient to hold the object item that corresponds to the selected dropdown element. Can anyone point out what might be going wrong?

javascript angularjs

Answer 1

Answer №1

It seems like your code is functioning correctly when tested on my end. The issue may lie in the initialization process or in another section of the code that hasn't been revealed.

angular.module("sampleApp", [])
  .controller("ingredientCtrl", function ($log, $scope) {
    $scope.availableIngredients = [
      {ingredient: "apple"},
      {ingredient: "banana"},
      {ingredient: "cherry"},
    ];
    $scope.selectedIngredient = null;
    $scope.selectIngredient = () => {
      $log.log($scope.selectedIngredient?.ingredient);
    };
  });

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.8.2/angular.js"></script>
<div ng-app="sampleApp" ng-controller="ingredientCtrl">
  <select
    ng-model="selectedIngredient"
    ng-options="item as item.ingredient for item in availableIngredients"
    ng-change="selectIngredient()"
  >
    <option value="">
      Choose an ingredient...
    </option>
  </select>
</div>

Answer 2

It seems like your code is functioning correctly when tested on my end. The issue may lie in the initialization process or in another section of the code that hasn't been revealed.

angular.module("sampleApp", [])
  .controller("ingredientCtrl", function ($log, $scope) {
    $scope.availableIngredients = [
      {ingredient: "apple"},
      {ingredient: "banana"},
      {ingredient: "cherry"},
    ];
    $scope.selectedIngredient = null;
    $scope.selectIngredient = () => {
      $log.log($scope.selectedIngredient?.ingredient);
    };
  });

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.8.2/angular.js"></script>
<div ng-app="sampleApp" ng-controller="ingredientCtrl">
  <select
    ng-model="selectedIngredient"
    ng-options="item as item.ingredient for item in availableIngredients"
    ng-change="selectIngredient()"
  >
    <option value="">
      Choose an ingredient...
    </option>
  </select>
</div>

Answer 3

Answer №2

Shoutout to @billy_comic for the helpful workaround shared in the comments section!

<select ng-model="$parent.selected_ingredient"
        ng-options="item as item.name for item in available_ingredients"
        ng-change="$emit( 'SelectedIngredient', $parent.selected_ingredient )">
    <option value="">Add an ingredient...</option>
</select>

I incorporated this code snippet into my HTML, along with the following JS function:

$scope.$on( "SelectedIngredient" , function( evt, data ) {
    if ( $scope.debug > 0 ) {
        console.log( "Selected ingredient:" );
        console.log( data );
    }
});

Everything is working smoothly and I'm getting the desired results. Big thanks!

Answer 4

Shoutout to @billy_comic for the helpful workaround shared in the comments section!

<select ng-model="$parent.selected_ingredient"
        ng-options="item as item.name for item in available_ingredients"
        ng-change="$emit( 'SelectedIngredient', $parent.selected_ingredient )">
    <option value="">Add an ingredient...</option>
</select>

I incorporated this code snippet into my HTML, along with the following JS function:

$scope.$on( "SelectedIngredient" , function( evt, data ) {
    if ( $scope.debug > 0 ) {
        console.log( "Selected ingredient:" );
        console.log( data );
    }
});

Everything is working smoothly and I'm getting the desired results. Big thanks!

Variable scope fails to update upon selection change

Answer №1

Answer №2

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