Plurrrr

The visitor design pattern in Swift allows us to add new features to an existing group of objects without altering the original code.

To hear some people talk, you’d think function composition was some kind of sacred truth. A holy principle to meditate upon whilst genuflecting and lighting incense. But function composition is not complicated. You probably use it all the time, whether you realise it or not. Why, then, do functional programmers get all worked up about it? What’s the big deal?

If you are a JavaScript developer, you might want to programmatically detect whether dark mode is enabled in the user’s operating system and seamlessly adapt your app.