Write Your Own React-Redux Connect

My inspiration for this blog post came from this video where Dan Abramov walks through the source code to react-redux

As frontend web developers, it's not uncommon that we follow well-specified patterns - often blindly. The frontend landscape is changing rapidly, and sometimes there isn't time to investigate why we use a specific pattern; we just know we should.

One widely used pattern in react-redux applications looks like this


I'll assume you know how to implement this pattern, but why do we use it and how does it work under the hood?