Renderers
There are several renderers that could be used to visualize the simulation:

Renderer does not contain any implementation and can be used as a mock if there is no need to provide visual layer. It is an interface and thus acts as a base class for all other renderers.
AbstractRenderer provide the most basic implementation. It maps views with models and within each render loop, it updates views according to related models. This is an abstract renderer and should not be used directly with the simulation.
AbstractPixiRenderer include common mechanisms required to render battle with PixiJS engine. This is an abstract renderer and should not be used directly with the simulation.
Other Renderers provide various visualization of the Battle. BrodyRenderer is the default one used in JSBattle
Views
AbstractRenderer introduce a concept of View, that is mapped with related Model and visualize its state. There are several types of Views used by different Renderers

Each view stores reference to the linked model. Properties of the model are read during View.update() call and the view is being updated accordingly.