Welcome. Free Books in the Fun Press Series about Functional Programming in JavaScript 'n' Friends include:
You Don't Know JS: Up & Going by Kyle Simpson (Source in the Manuscripts book format, Original Sources) Star
ECMAScript 6 Features by Luke Hoban et al (Source in the Manuscripts book format, Original Sources) Star
Babel User Guide by James Kyle et al (Source in the Manuscripts book format, Original Sources) Star
Professor Frisby's Mostly Adequate Guide to Functional Programming in JavaScript by Brian Lonsdorf (Source in the Manuscripts book format, Original Sources) Star