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JavaScript AngularJS An Introduction to Two-Way Data Binding User Interactions

Posted by John Naulty
John Naulty
1,169 Points

Why do you pass newValue and oldValue in the function in $watch when you don't use oldValue?

I am under the assumption that the function $scope.$watch will get called whenever the message being watched gets called. I don't understand why you pass oldValue in the listener function.

1 Answer

jason phillips
jason phillips
18,131 Points
jason phillips
jason phillips
18,131 Points

You don't need to pass the old value, but it is there if you need it.

$scope.$watch('item', function(newVal){

});