3v0k4

const Result = require('folktale/result')
const R = require('ramda')

const first = xs => Result.fromNullable(xs[0])

const parse = s => Result.try(() => JSON.parse(s))

const upper = s => s.toUpperCase()

const shout = s => s.concat('!')

3v0k4

const Result = require('folktale/result')

const first = xs => Result.fromNullable(xs[0])

const parse = s => Result.try(() => JSON.parse(s))

const upper = s => s.toUpperCase()

const shout = s => s.concat('!')

3v0k4

const Right = x =>
  ({
    x,
    map: f => Right(f(x)),
    inspect: _ => `Right(${x})`,
    isLeft: _ => false,
    chain: f => f(x),
  })

const Left = x =>

3v0k4

const Right = x =>
  ({
    x,
    map: f => Right(f(x)),
    inspect: _ => `Right(${x})`,
    isLeft: _ => false,
    chain: f => f(x),
  })

const Left = x =>

3v0k4

const parse = s => tryCatch(() => JSON.parse(s))

const first = xs => fromNullable('empty array', xs[0])

const upper = s => s.toUpperCase()

const shout = s => s.concat('!')

3v0k4

const toString = i => String(i) // <-- added this

const functional = s =>
  Right(s)
  .chain(parse)
  .chain(first)
  .map(toString) // <-- added this
  .chain(format)

const functional2 = ss => ss.map(functional) // <-- added this

3v0k4

// tryCatch :: Function => Either(String)
const tryCatch = f => {
  try {
    return Right(f())
  } catch (e) {
    return Left('could not parse')
  }
}

// parse :: String -> Either [String]

3v0k4

// upper :: String -> String
const upper = s => s.toUpperCase()

// shout :: String -> String
const shout = s => s.concat('!')

// format :: String => Either(String)
const format = s => 
  Right(s)
  .map(upper)

3v0k4

Right(1).map(x =>
  Right(2).map(y => x + y)) // Right(Right(3))

Right(1).chain(x =>
  Right(2).map(y => x + y)) // Right(3)

3v0k4

const Right = x =>
  ({
    x,
    map: f => Right(f(x)),
    chain: f => f(x)
  })

const Left = x =>
  ({
    x,