The store contains your application's state.
Access the store's state via getState.
Reducers maintain the state.
Reducers calculate the next state and return it.
Reducers take two parameters: the current state and an action.
Actions are objects.
All actions have a type property.
Update the store via dispatch(action).
store.subscribe(listener) adds a change listener which is called any time an action is dispatched.
Redux with React.