Where did "editing" in ng-hide="editing" or ng-click=" editing = !editing" come from?

It came from nowhere! It was created as a property of the current scope by the ng-click directive that was attached to the edit anchor/button.

Basically, when you click on the anchor/button the first time, Angular says "You want to change the property called 'editing' to be the opposite of what it is? Do I have a property called 'editing'? No, I don't. I guess I'll make it!" And thus the mainCtrl scope gets a property named 'editing'. Since it didn't exist yet, Angular assumes that means about the same as 'false' and so running the 'make me opposite' expression on it turns it to 'true'.

It's very convenient and powerful to create scope properties on the fly like this, but also understandably confusing to beginners who are accustomed to declaring all the properties ahead of time. But as you get more into programming, you'll see this done in lots of situations.

Thanks Marco, I understand what "editing" does and how it used, but what I don't get is from where did it came? Could I have put "zebras" instead of "editing" and get the same results? Actually let me check that.

Ok. So "zebras" works just as "editing" worked. Which means that "editing" is a made up name.

hey, i think it's an attribute of the object todo or post or whatever. In this case the attribute editing is a boolean it means it can be true or false. the angularjs ng-click directive in this case switch the value of $scope.todo.editing from true to false and viceversa when the tag is clicked

hope it helps