Paths for functional pipes

path.js

import {
  curryN,
  update,
  nth
} from 'ramda'

// Getting an array, modify just one its elements allowing different pipes in a data structure
// Number -> Function -> Array -> Array
const path = curryN(
  3,
  (index, functor, datum) => update(
    index,
    functor(nth(index, datum))
    datum
  )
)

/*
Example:

const add1 = add(1)
const add9 = add(9)

// numberOfElements -> valueToFullFill -> List
// ex: fill(2, 3) === [3, 3]
const fill = flip(repeat)

const usePath = curryN(
  3,
  (index, functor, datum) => update(
    index,
    functor(nth(index, datum)),
    datum
  )
)

const do_x_plus_9_divided_by_x_plus_1 = compose(
  apply(divide),
  usePath(0, add9),
  usePath(1, add1),
  fill(2)
)

do_x_plus_9_divided_by_x_plus_1(1)
*/