Angular 1.X -

Decorators

Decorators are good for adding logic to a third party library e.g. logging or benchmarking.

myModule.controller('MainCtrl', function (foo) {
  foo.bar();
});

myModule.factory('foo', function () {
  return {
    bar: function () {
      console.log('I\'m bar');
    },
    baz: function () {
      console.log('I\'m baz');
    }
  };
});

myModule.config(function ($provide) {
  $provide.decorator('foo', function ($delegate) {
    var barBackup = $delegate.bar;
    $delegate.bar = function () {
      console.log('Decorated');
      barBackup.apply($delegate, arguments);
    };
    return $delegate;
  });
});