Combating AngularJS executing controller twice

👋 Hey there! Do you have a problem with AngularJS executing your controller twice? Don't worry, you're not alone! It can be quite frustrating when your code ends up inserting duplicate records into your database. But fear not, because I'm here to help! 🦸‍♀️

Before we dive into the solutions, let's understand why your controller is executing twice. As you mentioned, AngularJS runs through some code multiple times, especially when it encounters $watch events or needs to continually check model states. But in your case, it seems that there might be another reason causing this issue.

Looking at your code snippet, I can see that you have a function named "MyController" that takes in three parameters: $scope, User, and local. Inside this function, you're assigning the result of local.get() to a variable called "$scope.User". Then, you make an asynchronous call to User.get(), which retrieves the user data based on the $scope.User._id.$oid. Once the data is fetched, you reassign it to $scope.User and save it locally using local.save($scope.User).

Now, the problem arises because this code is executed twice, resulting in duplicate DB records. 😥

Now that we have a better understanding of the issue, let's explore some simple solutions to combat AngularJS executing your controller twice:

Solution 1: Use the ng-if Directive One common approach to resolving this issue is to use the ng-if directive. Wrap the element where your controller is being used with ng-if, and provide a condition that ensures the controller only executes once. Here's an example of how you can implement this:

<div ng-if="!isExecuted" ng-init="isExecuted = true" ng-controller="MyController">
  <!-- Your controller code goes here -->
</div>

In this solution, we introduced a variable called "isExecuted" and set it to false by default. The first time the controller is executed, the condition "!isExecuted" is true, and the code inside the ng-if block will be executed. Additionally, we set "isExecuted" to true using ng-init, ensuring the controller won't run again.

Solution 2: Use the $routeChangeSuccess Event Another way to prevent your controller from executing twice is by leveraging the $routeChangeSuccess event. This event is emitted when a route change occurs. You can make use of this event to trigger your controller's execution only once. Here's an example:

app.controller('MyController', function($scope, $rootScope, User, local) {
  var isFirstLoad = true;
  
  $rootScope.$on('$routeChangeSuccess', function() {
    if (isFirstLoad) {
      // Your controller code goes here
      isFirstLoad = false;
    }
  });
});

With this solution, we introduced a boolean variable called "isFirstLoad" to keep track of whether it's the first time the controller is being executed. When the $routeChangeSuccess event is triggered, we check if it's the first load. If so, we execute the controller code and set "isFirstLoad" to false.

These solutions should help you combat AngularJS executing your controller twice. Give them a try and see which one works best for your situation!

Now, before we wrap up, I'd love to hear your thoughts! Have you faced this issue before? How did you solve it? Share your experience in the comments below. Let's help each other out! 🤝

Until next time, happy coding! 💻✨