# Overview
typed-ecstasy comes with a few Entity Systems that will spare you from typing boilerplate code.
Make sure to check out the page about Dependency Injection. All built-in EntitySystems require constructor arguments, so you'll need to create constructors, which call the super-constructor.
- IteratingSystem: Iterate over a Family of entities
- IntervalSystem: Run code at a constant interval
- IntervalIteratingSystem: Iterate over a Family of entities at a constant interval
- SortedIteratingSystem: Iterate over a sorted Family of entities
- SortedSubIteratingSystem: Imagine a SortedIteratingSystem that you can add SubSystems to