Trying to assign an array to $scope is causing issues

Question

Trying to assign an array to $scope is causing issues

I have an array called `arr` in a function that I want to return to `$scope.notifications` so that I can use it in the HTML within the Ionic Framework. I want to use a function to perform certain actions with the array before returning it later on. Here is my controller:

.controller('notificationsCtrl', function($scope) {
    $scope.notifications = function(){
        var arr = [
            {user:"misterx", name:"Mister X", action:4, image: "https://www.holidaycheck.de/mediaproxy?target=hcaHR0cDovL3d3dy5ob3RlbC5kZS9tZWRpYS9ob3RlbC9waWN0dXJlcy8zMzQvMzM0MTIzL0V4dGVyaW9yXzYzNTkyNzk5NDMyODQ1OTAwMi5qcGc%3D"},
            {user:"misterx", name:"Mister X", action:2, image: "https://www.holidaycheck.de/mediaproxy?target=hcaHR0cDovL3d3dy5ob3RlbC5kZS9tZWRpYS9ob3RlbC9waWN0dXJlcy8zMzQvMzM0MTIzL0V4dGVyaW9yXzYzNTkyNzk5NDMyODQ1OTAwMi5qcGc%3D"},
            {user:"ladyx", name:"Lady X", action:1}
        ];
        return arr;
    }
})

The HTML:

<ion-item ng-repeat="msg in notifications" class="item-text-wrap">
    <div class="row">
        <div class="col-80">
            <strong>{{msg.name}}</strong> (<em>@{{msg.user}}</em>) {{msg.action}}.
        </div>
        <div class="col-20">
            <img src="{{msg.image}}" style="border-radius: 50px; width: 100%">
        </div>
    </div>
</ion-item>

When I directly pass notifications as an array without using a function, it works. What am I missing here?

javascript arrays angularjs ionic-framework

Answer 1

Answer №1

When using ng-repeat="msg in notifications", it attempts to repeat over the function itself rather than its return value. To correctly iterate through the list, you should call the function like this:

<ion-item ng-repeat="msg in notifications()">

Visit this link for an example.

It's important to note that there may be performance issues with this method. The function will be called frequently because Angular cannot anticipate whether the function's result will change. It is recommended to store "notifications" as a regular array in the scope instead. Any changes made to that array will automatically prompt the component to re-render with the updated values:

  $scope.notifications = [{
    user: "misterx",
    name: "Mister X",
    //...
  }];

  $scope.addNotification = function() {
    $scope.notifications.unshift({
      user: "newguy",
      name: "New Guy"
    });
    // Angular will detect the change in notifications[] and re-render the component during the next $digest cycle
  };

Take a look at this link for a demonstration.

Answer 2

When using ng-repeat="msg in notifications", it attempts to repeat over the function itself rather than its return value. To correctly iterate through the list, you should call the function like this:

<ion-item ng-repeat="msg in notifications()">

Visit this link for an example.

It's important to note that there may be performance issues with this method. The function will be called frequently because Angular cannot anticipate whether the function's result will change. It is recommended to store "notifications" as a regular array in the scope instead. Any changes made to that array will automatically prompt the component to re-render with the updated values:

  $scope.notifications = [{
    user: "misterx",
    name: "Mister X",
    //...
  }];

  $scope.addNotification = function() {
    $scope.notifications.unshift({
      user: "newguy",
      name: "New Guy"
    });
    // Angular will detect the change in notifications[] and re-render the component during the next $digest cycle
  };

Take a look at this link for a demonstration.

Answer 3

Answer №2

No function is required to return JSON format for the following code:

.controller('notificationsCtrl', function($scope) {
$scope.notifications = [
        {user:"misterx", name:"Mister X", action:4, image: "https://www.holidaycheck.de/mediaproxy?target=hcaHR0cDovL3d3dy5ob3RlbC5kZS9tZWRpYS9ob3RlbC9waWN0dXJlcy8zMzQvMzM0MTIzL0V4dGVyaW9yXzYzNTkyNzk5NDMyODQ1OTAwMi5qcGc%3D"},
        {user:"misterx", name:"Mister X", action:2, image: "https://www.holidaycheck.de/mediaproxy?target=hcaHR0cDovL3d3dy5ob3RlbC5kZS9tZWRpYS9ob3RlbC9waWN0dXJlcy8zMzQvMzM0MTIzL0V4dGVyaW9yXzYzNTkyNzk5NDMyODQ1OTAwMi5qcGc%3D"},
        {user:"ladyx", name:"Lady X", action:1}
    ];

}

})

Answer 4

No function is required to return JSON format for the following code:

.controller('notificationsCtrl', function($scope) {
$scope.notifications = [
        {user:"misterx", name:"Mister X", action:4, image: "https://www.holidaycheck.de/mediaproxy?target=hcaHR0cDovL3d3dy5ob3RlbC5kZS9tZWRpYS9ob3RlbC9waWN0dXJlcy8zMzQvMzM0MTIzL0V4dGVyaW9yXzYzNTkyNzk5NDMyODQ1OTAwMi5qcGc%3D"},
        {user:"misterx", name:"Mister X", action:2, image: "https://www.holidaycheck.de/mediaproxy?target=hcaHR0cDovL3d3dy5ob3RlbC5kZS9tZWRpYS9ob3RlbC9waWN0dXJlcy8zMzQvMzM0MTIzL0V4dGVyaW9yXzYzNTkyNzk5NDMyODQ1OTAwMi5qcGc%3D"},
        {user:"ladyx", name:"Lady X", action:1}
    ];

}

})

Trying to assign an array to $scope is causing issues

Answer №1

Answer №2

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