AngularJS implementation method for listening for variable changes

As shown below:

var timeout;
$scope.$watch('',function (newVal, oldVal) {
 if (newVal !== oldVal) {
  if (timeout) $(timeout);
  timeout = $timeout(function() {
   $();
  }, 800);
 }
}, true);

The above method of implementing the AngularJS monitoring variable changes is all the content I have shared with you. I hope you can give you a reference and I hope you can support me more.