how to ensure a consistent property value across all scopes in AngularJS

Question

how to ensure a consistent property value across all scopes in AngularJS

Here is my perspective

  <div ng-if="isMultiChoiceQuestion()">
                <li class="displayAnswer" ng-repeat="choice in getMultiChoice() track by $index" ng-if="isNotEmpty(choice.text.length)">
                            <input type="checkbox" ng-checked="checkForSelection(choice.id)"
                            value="choice.text" disabled="true">
                      <span ng-class="getCSSClass($index, choice.id)">{{choice.text}}</span>
                </li>
              </div>

            <a class="weiter-link" ng-click="flipBack()">Zur Frage</a>

                <div ng-if="isMultiChoiceQuestion()">
                  <!--Changed ng-bind getScore() -> score -->
                      <h4>Bewertung speichern: <span ng-bind="getScore()"></span></h4>
                  <br />
                      <a class="weiter-link" ng-click="incrementOne()">Zur nächsten Frage</a>
                </div>
                  <div ng-if="!isMultiChoiceQuestion()">
                        <h3>Eigene Bewertung: {{score}}</h3>
                        <div class="ranger">
                          <input type="range" max="10" min="0" step="1" id="selfRanger" ng-model="score">
                        </div>
                        <a class="weiter-link" ng-click="submitScore(score)">Bewertung speichern</a>
                            <a class="weiter-link" ng-click="incrementOne()">Zur nächsten Frage</a>
            </div>

The above view creates three scopes. One for the controller, another for the first div, and the third for the second div. The issue lies with the property called "score" in the controller not being utilized in the second div.

How can we make the second div utilize the controller's property instead of automatically creating its own property?

JavaScript

app.controller("QuizController", ['total', '$scope', '$rootScope',  'quizDataService',  'QAPointerChange', 'QAScoreList', function (total, $scope, $rootScope, quizDataService, QAPointerChange, QAScoreList) {

  $scope.getScore = function()
      {
          // Makes a call to getCurrentScore and returns a value
          $scope.getCurrentScore();
          return QAScoreList.getSpecificItemScore(QAPointerChange.getQAPointer());
      }
$scope.score = 0;

    $scope.submitScore = function (newScore)
    {
        QAScoreList.setSpecificItemScore(QAPointerChange.getQAPointer(), Number(newScore));
    }


      $scope.getCurrentScore = function()
      {
            $scope.score = QAScoreList.getSpecificItemScore(QAPointerChange.getQAPointer());
      }


}

This is not a complete JS file. The controller has all services responsible for making calls to fetch scores and other data from services.

javascript angularjs

Answer 1

Answer №1

If you want to utilize nested scopes, there are two methods:

Dot Notation

Avoid using a single variable like $scope.score, but instead use $scope.data.score (your variable is within an object which is inside the scope).

Controller as Syntax

Do not assign variables to the scope, but to the controller (at the beginning of the controller):

var self = this;
self.score = 5;

In the HTML:

<div ng-controller="QuizController as ctrl">

And then use it like this:

{{ctrl.score}}

Update on Slider Issue

The issue with the slider getting stuck: You have ng-bind="getScore()" in your HTML so getScore is executed every $digest cycle. This occurs when the HTML needs to be redrawn, such as when a scope variable changes. So:

When you adjust the slider, $scope.current.score changes
As a result, the $digest cycle begins
getScore is executed
$scope.current.score is updated with the value from QAScoreList in the getCurrentScore function
The slider reverts back to that value

It worked without dot notation because both $scope.score and ng-model="score" were not the same variable (they existed in different scopes)

Therefore, it would be advisable to do the following (assuming that in "Bewertung speichern" you want to display the same value as selected in the range, if not, you must use a different variable name):

Replace ng-bind="getScore()" with ng-bind="current.score"
Execute $scope.getScore() at the start of the controller to retrieve the current value from the service QAScoreList

Answer 2

If you want to utilize nested scopes, there are two methods:

Dot Notation

Avoid using a single variable like $scope.score, but instead use $scope.data.score (your variable is within an object which is inside the scope).

Controller as Syntax

Do not assign variables to the scope, but to the controller (at the beginning of the controller):

var self = this;
self.score = 5;

In the HTML:

<div ng-controller="QuizController as ctrl">

And then use it like this:

{{ctrl.score}}

Update on Slider Issue

The issue with the slider getting stuck: You have ng-bind="getScore()" in your HTML so getScore is executed every $digest cycle. This occurs when the HTML needs to be redrawn, such as when a scope variable changes. So:

When you adjust the slider, $scope.current.score changes
As a result, the $digest cycle begins
getScore is executed
$scope.current.score is updated with the value from QAScoreList in the getCurrentScore function
The slider reverts back to that value

It worked without dot notation because both $scope.score and ng-model="score" were not the same variable (they existed in different scopes)

Therefore, it would be advisable to do the following (assuming that in "Bewertung speichern" you want to display the same value as selected in the range, if not, you must use a different variable name):

Replace ng-bind="getScore()" with ng-bind="current.score"
Execute $scope.getScore() at the start of the controller to retrieve the current value from the service QAScoreList

Answer 3

Answer №2

By using the ng-if directive to call a function, the function will only be executed when the specified condition is met. To ensure that the getScore() function is not skipped for the third div, you can use the ng-init='getScore()' attribute in the third div as well.

Answer 4

By using the ng-if directive to call a function, the function will only be executed when the specified condition is met. To ensure that the getScore() function is not skipped for the third div, you can use the ng-init='getScore()' attribute in the third div as well.

how to ensure a consistent property value across all scopes in AngularJS

Answer №1

Dot Notation

Controller as Syntax

Update on Slider Issue

Answer №2

Similar questions

I'm having trouble customizing the appearance of a Tab Panel using the TabsAPI. The panel keeps expanding in strange ways. How can I

Error encountered with the OpenAI API: "The module 'openai' does not have a defined export for 'Configuration'"

React component failing to render even when event is triggered

What is the method to extract a value from the $emit payload using Vue.js?

Emptying the trumbowyg editor within an Angular environment

Is it possible to alter the name of a slot before displaying the element in the shadowDOM, depending on the slot utilized in the DOM?

Retrieve data from the table and dropdown menu by clicking a button

Executing a function without using the eval() function

Alternative to using the disabled attribute in JavaScript to make a checkbox read-only option

Encountering a problem with Selenium when dealing with tabular data displayed in a DIV format on a website, where each row is encapsulated within its own DIV element

Best method for linking asynchronous requests using axios

The angular.js routing feature seems to be malfunctioning as the view is not loading properly

Inserting items into an array entity

Type of result from a function that returns a linked promise

Ways to retrieve property value from a component in Vue.js 2.0

Error in React-router: Unable to assign value to the 'props' property as it is undefined

Display a pleasant alert message when the file is not recognized as an image during the loading

How can I insert my URL into the webPDFLoader feature of LangChain platform?

Browsing a container with JavaScript

I require the ability to retrieve only the data from a UI grid column, specifically based on the column name selected