Javascript / Nodejs

it's multi-paradigm: scripting, object-oriented (prototype-based), imperative, functional ( source: https://en.wikipedia.org/wiki/JavaScript )

Many languages known as functional (Scala, F#, Lisp, Scheme, OCaml) are multi-paradigm languages (check out Wikipedia!), purely functional programming language like Haskell are the exception (https://en.wikipedia.org/wiki/Purely_functional ). And the IO part is hardly functional.

@Down voter: care to explain?