This guide will use JavaScript instead of a pure functional programming language (e.g. Haskell) to make things more approachable for developers accustomed to imperative languages. It will, however, assume you have basic knowledge of functional programming, including currying and lambdas.
I know, I know, the world does not need yet another introduction to monads (or yet another article complaining that world does not need yet another introduction to monads). So you’ll be glad to know this isn’t one of those, in the sense that it’s not new