The idea of map is to transform a collection.
An Introduction to the basic principles of Functional Programming

TK The idea of map on a collection is to transform that collection. However, there is so much more to map. In broader terms, map can transform the wrapped value in other Functor and Monad types. This is a powerful concept when using map and flatMap on Either or Result types, to name a few. I hope you will touch on this in future articles. Good article. Keep them coming.