AngularJS Web Application Development Cookbook

Optimizing the application using reference $watch

Reference watches register a listener that uses strict equality (===) as the comparator, which verifies the congruent object identity or primitive equality. The implication of this is that a change will only be registered if the model the watcher is listening to is assigned to a new object.

How to do it…

The reference watcher should be used when the object's properties are unimportant. It is the most efficient of the $watch types as it only demands top-level object comparison.

The watcher can be created as follows:

$scope.myObj = { myPrim: 'Go Bears!', myArr: [3,1,4,1,5,9] }; // watch myObj by reference $scope.$watch('myObj', function(newVal, oldVal, scope) { // callback logic }); // watch only the ...