$scope vs var in AngularJS

Question

I\'ve been using var and $scope.varname and both work fine in AngularJS. I was wondering if there was a difference between the two functionally, and what best practice was i

Answer 1

The technical implications of using var and $scope have been described by @tymeJV and others. I think the next logical question answer is: When do I use either?

TL;DR - if you do not use a variable in a view (e.g. {{myVar}} ), use var.

The reason is two fold:

1. Encapsulation - hide state that is not necessary to the view. This will prevent unintended modifications of the variable.

2. Performance (prevent extra digest cycles) - Angular performs "dirty state" checking on variables. Modifying a variable that's not used in the view may cause extra digest cycles unnecessarily. In an application with a couple of ng-repeats and a bunch of watches, this can have a huge impact.