Why is a function in ng-repeat called several times?

Question

I want to supply a ng-repeat element by a controller function as follows:

        
                      

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Answer 1

a little bit about the digest cycle:

we need to check every time something in the application changes - what was effected by that change, and re-evaluate all the places that might depend on that change,

so that is why the function in the ng-repeat was called multiple times - it had to check wheter the repeated list is the same after some changes happend in the application

read more about the digest cycle and two-way data binding:

http://blog.bguiz.com/post/60397801810/digest-cycles-in-single-page-apps/

Answer 2

I would really avoid calling a function insides a ngRepeat attribute, since it will give errors and unexpected behaviour.

But to be honest I dont think that you would need to call a function inside a ngRepeat. I would suggest to do the following:

<div ng-repeat="picture in allPictures"></div>

$scope.getPictures = function(pictures) {
        alert("function called");
        //return... extract all pictures and return as array
};

$scope.allPictures = $scope.getPictures();

This way the $scope.getPictures function will get called and the $scope.allPictures will be created. ngRepeat can call that collection instead of a function.

See also my Fiddle: https://jsfiddle.net/ABr/w6kc8qyh/1/