How do I stop $watching in AngularJS?

Issue

I can set up a $watch on an AngularJS scope to be notified when the expression I am interested in has changed. But how do I stop watching once I lose interest?

Solution

When calling $watch a function is returned that unregisters the bound expression.

E.g., to watch a variable foo only change once:

var unregister = $scope.$watch('foo', function () {
  // Do something interesting here ...
  unregister();
});

Hope that helps :-)

Answered By - Golo Roden