notMonad.js

import { Async, identity } from 'crocks'

// A Promise is not a Functor, since it is not
// a functor it cannot be a Monad
Promise
  .resolve(Promise.resolve(3))
  .then(console.log)
//=> 3
// should return a Promise that will return 3

// nestedAsync :: Async e (Async e Number)
const nestedAsync =
  Async.of(Async.of(3))

// Async is a Functor and a Monad, it returns 
// the inner nested Async.
nestedAsync.fork(
  console.log.bind(console, 'rejected:'),
  console.log.bind(console, 'resolved:')
)
//=> logs "resolved: Async Function"

// Async is a Functor and a Monad, it can also
// join (the heart of the Monoid portion of a Monad)
// by chaining `identity`
nestedAsync
  .chain(identity)
  .fork(
    console.log.bind(console, 'rejected:'),
    console.log.bind(console, 'resolved:')
  )
//=> logs resolved: 3