ng-repeat looping over items twice?

[mike....@gmail.com]

I'm new to angular so this might be a dumb question, but why does ng-repeat iterate over every item twice? If you don't know what I'm talking about run this: http://plnkr.co/edit/dSmYH5 with the web console open.  There are 5 items but the helper function has been called 10 times.  Why is this necessary?

[Peter Bacon Darwin]

This is how angular works - it will run the ng-repeat directive as many times as it sees fit.

You are thinking too imperatively.  Do not put code to be repeated inside the template.  The template is declarative - it should describe what you want to see in the browser.

If you want to do processing on the data to be iterated over, do it in the controller before passing that data to the ng-repeat directive.

Pete

On 20 November 2012 05:33, <mike....@gmail.com> wrote:

I'm new to angular so this might be a dumb question, but why does ng-repeat iterate over every item twice? If you don't know what I'm talking about run this: http://plnkr.co/edit/dSmYH5 with the web console open.  There are 5 items but the helper function has been called 10 times.  Why is this necessary?

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[Nils Kilden-Pedersen]

Doesn't answer the question of why it's necessary. It does seem, at the very least, to be an inefficient way to process. Perhaps it's necessary, but it would be good to know why and if it's intrinsic.

[Pawel Kozlowski]

Hi Nils!

This is the best explanation I know of:
http://stackoverflow.com/a/9693933/1418796

Cheers,
Pawel

Question? Send a fiddle
(http://jsfiddle.net/pkozlowski_opensource/Q2NpJ/) or a plunk
(http://plnkr.co/)
Need help with jsFiddle? Check this:
http://pkozlowskios.wordpress.com/2012/08/12/using-jsfiddle-with-angularjs/

Looking for UI widget library for AngularJS? Here you go:
http://angular-ui.github.com/

[Nils Kilden-Pedersen]

Ok, so essentially due to the two-way binding nature of angular, right?

If so, that makes sense.

[Pawel Kozlowski]

Hi!

Yes, basically AngularJS uses dirty-checking to figure out what (and
when) to repaint. Please note that this dirty checking might be
trigger by user's input (I guess this is what you mean by 2-way data
binding) as well as some async events ($timeout, $http calls etc.).

Another SO question that might explain why the whole data model must
be re-calculated: http://stackoverflow.com/q/12333410/1418796

Cheers,
Pawel