core/common/extension-hooks.ts
        
Extension points allow to extend the application from any module
| Properties | 
| Methods | 
| refresh | 
| refresh() | 
| Call the extension factories to refresh them. 
                            Returns :          any | 
| factories | 
| factories:          | 
| Type : ExtensionFactory<T>[] | 
| Additional factories that can be added dynamically. (without hook) | 
| items$ | 
| items$:      | 
| Type : Observable<T[]> | 
| Observable that emits of array of extensions active at any give time |