Angular's bidirectional binding feature seems to be malfunctioning when integrated with Firebase

I'm facing an issue with displaying a list of products from my firebase database. Despite updating the $scope.products array and seeing it reflected in the console log, the changes are not being reflected on the user interface.

app.controller("productManagerController", ["$scope", function ($scope) {
    $scope.products = [];
    db.ref("products").once('value').then(function (snapshot) {
        const values = snapshot.val()
        for (key in values) {
            values[key].id = key;
            $scope.products.push(values[key])
        }
        console.log($scope.products) // The values retrieved from firebase are logged
                                    // However, UI doesn't update accordingly

    })
}])

Answer №1

In addition to Sajeetharan's response, there is a helpful article on this link that delves into why utilizing $scope.$apply() resolves the issue.

When Should You Manually Invoke $apply()?

If AngularJS typically encapsulates our code within $apply() and initiates a $digest cycle, then when is it necessary for us to manually call $apply()? AngularJS explicitly states one key point. It only tracks model changes made within its own context (i.e., modifications to models enclosed in $apply()). Angular's predefined directives already handle this process, ensuring that any alterations to models are displayed in the view. However, if you modify a model outside of Angular's realm, you need to notify Angular about these changes by manually invoking $apply(). This action informs Angular that model adjustments have been made, prompting it to run watchers so the modifications are properly reflected.

Essentially, since the db.ref(..)... invocation is not enveloped in an $apply block as it lies outside of AngularJS' domain, you must trigger it on your own.

Answer №2

If you want to implement changes automatically with Firebase, you can use the following method: $scope.$apply();

 $scope.products.push(values[key])
 $scope.$apply();

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