ACF: Load and save fields to a custom plugin

It’s not always that you want to save your ACF-JSON fields to your theme folder, like when you’re creating a custom plugin for a new client that depends on ACF, or when using a theme that’s not within your development.

For these cases ACF has a nice function; you can filter it so that it saves the fields to a folder you define.

All three examples that you see below do exactly the same thing, but in various ways. The first example is best, as it’s re-useable and easy to understand for developers.