public protocol Middleware
Middleware perform actions on the the store when actions are dispatched to it.
Before an action is given to a reducer, middleware have an opportunity to handle it themselves. They may dispatch their own actions, transform the current action, or block an incoming ones from continuing.
Middleware can also be used to set up external hooks from services.
For a reducer’s own state and actions, implement the
For subreducers, implement the
Compose two middleware together.
The middleware to be called first.
The next middleware to call.
The combined middleware.