Learning Redux

What is middleware?

Middleware is a JavaScript pattern, similar to the Chain of Responsibility (CoR) pattern, where a chain of functions is used to handle an incoming event, often in the form of a request.

This pattern is especially useful in libraries that deal with events (such as requests in express or actions in Redux). The middleware pattern has several benefits:

• It allows us to do the following:
  • Use several functions to handle the event and process the data
  • Have functions act as a filter for certain kinds of data
• It doesn't require explicit knowledge between sender and receiver
• The chain of functions can be changed during runtime, acting as an event pipeline

Certain libraries, such as express, allow you to extend their functionality ...