Explore the Mediator, State, and Command behavioral design patterns, including how to implement them for modeling communication between components, in this 12-video course. Discover how to perform valid state transitions, implement the State pattern in React, and execute and undo commands. Key concepts covered here include characteristics of Mediator pattern, which is responsible for mediating communication between different components that exist in a system; how to set up Mediator as a workflow object; and how to use Mediator for communication. You will learn about characteristics of State pattern, which allows an object to alter its behavior, its display, or the way it reacts to events when its state changes; how to set up helper methods for State pattern; and how to implement State pattern in React. Continue by learning how to perform valid state transitions; observing characteristics of Command pattern, which is often used in order to implement undo and redo functionality in several applications; learning to implement Command pattern; and how to execute and undo commands.