In reactjs, middleware is a piece of code that bridges two or more parts of an application. Thunk is also a piece of software that is primarily used to delay a calculation until its result is needed, or to insert operations at the beginning or end of the other subroutine. Redux-logger, as the name suggests, it is simply a logger. It is used to spit out information about the previous and current state of an application that uses redux.
I hope this was brief.
Please refer to this, this and this to learn about these technologies in depth.
solved Description of reactjs reducer related terms [closed]