Transducers (performant in disguise)

"Transducers are composable algorithmic transformations. They are independent from the context of their input and output sources and specify only the essence of the transformation in terms of an individual element. Because transducers are decoupled from input or output sources, they can be used in many different processes - collections, streams, channels, observables, etc. Transducers compose directly, without awareness of input or creation of intermediate aggregates."

Wa-wa-what?

Let's review and demystify transducers, these little mechanisms help optimise performance, and abstract some of the pain of trying to watch each function for it's data structures.