How does the $provide.decorator method enhance or modify AngularJS services?

$provide.decorator modifies existing services by wrapping them, adding functionality like logging or custom behavior while preserving original functionality. This is useful for adjusting services, adding logging or profiling, without changing source code, enhancing flexibility and control.

$provide.decorator('$log', function($delegate) {
  return function(msg) {
    $delegate(msg + ' decorated');
  };
});