+1 for Ramda -- I've been using it for around 2 years now and once you get comfortable with how to compose it's various functions (and some of your own) it's super powerful. Might not be the best choice if your team is allergic to FP though, some people have a difficult time wrapping their head around it (or just getting used to the syntax). I've gone out of my way to document everything thoroughly knowing people who are mostly unfamiliar with FP will be looking at it though, and that's kept everyone happy.