In this post we will explore some boundaries of functional programming in Javascript and show how easy it is to implement a set of combinators that can express functions similar to queries in XPath and similar to transformations in XSLT. We call the result a combinator library because we implement a few primitive queries and transformations and allow combining these into bigger ones using some basic composition functions. As we will show, all functions will follow more or less the same structure.
This post is really about Javascript, which will be the target language of this library. But most of the techniques and underlying thoughts actually come from a statically typed functional programming background. While reading this post it might be interesting to continuously keep in mind the types of the functions, which makes it much easier to understand what is going on and how this framework might be extended with more interesting transformations.
(Link: Reinventing XSLT in pure Javascript — lablog)