Running AngularJS initialization code when view is loaded -- [Question Asked]

Query asked by user

When I load a view, I’d like to run some initialization code in its associated controller.

To do so, I’ve used the ng-init directive on the main element of my view:

<div ng-init="init()">
  blah
</div>

and in the controller:

$scope.init = function () {
    if ($routeParams.Id) {
        //get an existing object
        });
    } else {
       //create a new object
    }

    $scope.isSaving = false;
}

First question: is this the right way to do it?

Next thing, I have a problem with the sequence of events taking place. In the view I have a ‘save’ button, which uses the ng-disabled directive as such:

<button ng-click="save()" ng-disabled="isClean()">Save</button>

the isClean() function is defined in the controller:

$scope.isClean = function () {
    return $scope.hasChanges() && !$scope.isSaving;
}

As you can see, it uses the $scope.isSaving flag, which was initialized in the init() function.

PROBLEM: when the view is loaded, the isClean function is called before the init() function, hence the flag isSaving is undefined. What can I do to prevent that?

Answer we found from sources

When your view loads, so does its associated controller. Instead of using ng-init, simply call your init() method in your controller:

$scope.init = function () {
    if ($routeParams.Id) {
        //get an existing object
    } else {
        //create a new object
    }
    $scope.isSaving = false;
}
...
$scope.init();

Since your controller runs before ng-init, this also solves your second issue.

Fiddle

As John David Five mentioned, you might not want to attach this to $scope in order to make this method private.

var init = function () {
    // do something
}
...
init();

See jsFiddle

If you want to wait for certain data to be preset, either move that data request to a resolve or add a watcher to that collection or object and call your init method when your data meets your init criteria. I usually remove the watcher once my data requirements are met so the init function doesnt randomly re-run if the data your watching changes and meets your criteria to run your init method.

var init = function () {
    // do something
}
...
var unwatch = scope.$watch('myCollecitonOrObject', function(newVal, oldVal){
                    if( newVal && newVal.length > 0) {
                        unwatch();
                        init();
                    }
                });

Answered By – Mark Rajcok

This Answer collected from stackoverflow, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0