What are “decorators” and how are they used?

Question

I\'m curious what exactly decorators are in AngularJS. There isn\'t much information online for decorators save for a blurb in the AngularJS documentation and a brief (albei

Answer 1

In short decorators can be described as follows :-

A decorator function intercepts the creation of a service, allowing it to override or modify the behavior of the service.

It uses the $provide service by angular and modify or replaces the implementation of another service

$provide.decorator('service to decorate',['$delegate', function($delegate) {
  // $delegate - The original service instance, 
  //             which can be replaced, monkey patched, 
  //             configured, decorated or delegated to. 
  //             ie here what is there in the 'service to decorate'

  //   This function will be invoked, 
  //   when the service needs to be provided 
  //   and should return the decorated service instance.
  return $delegate;
}]);

Example:

$provide.decorator('$log', ['$delegate', function($delegate) {
  // This will change implementation of log.war to log.error
  $delegate.warn = $delegate.error; 
  return $delegate;
}]);

Applications

In addition to @JBland answer.

• Application wide locale settings :-

  You can find an example here

• Changiging default behaviour of and existing implementation of a service by angular service :-

  You can find an eample here

• Switching behavior of a function in different environments.