Javascript minimal FP library as declared by @JAForbes

miniFP.js

const toMaybe = x => x == null ? [] : x
const fromMaybe = (a, Ma) => Ma.concat( a ).pop()
const Just = x => [x]
const Nothing = []
const isJust = Ma => Ma.length > 0

const T = a => f => f(a)
const I = x => x
const K = a => () => a

const get = k => o => toMaybe(o[k])

const maybe = (b, f) => Ma =>
    fromMaybe( b, Ma.map( a => f(a) ))(Ma)

module.exports = {
    toMaybe
    ,fromMaybe
    ,maybe
    ,Nothing
    ,Just
    ,isJust
    ,get
    ,T
    ,I
    ,K
}