This is a quicky article.
I am going to explain what is middleware in Redux and what is Thunk.
If you don’t understand Redux well enough, I suggest that you read my article on Redux.
What is middleware?
Reducers in Redux must be always pure functions, which means you CAN’T do any side-effects (e.g fetch API).
Now, this is a problem because you can’t have an “async” logic in your application which means for example you can’t fetch data from an API.
Middleware in Redux is a utility placed between the
dispatch method and the reducer.
What is Thunk?
Thunk basically is a way to write async functions in Redux.
Let’s break it down!
1- Dispatch the action creator
In React, you dispatch an action creator
2- A function (action creator) that creates functions 🤔
fetchProducts is an action creator that takes
dispatch as an argument and returns a new function, inside of this function you can do any async operation.
After the async logic is done, the new function dispatch a new action creator
productSuccess with the data returned from the fetch.
3- An action creator that actually returns an action 🙃
productSuccess is an action creator that returns an action along with the returned data as a
This is the magic of middleware, It is almost like an extension or add-on!
Thank you for reading :)