monad$.js

import {
  from,
  just,
} from 'comea'

const log = label => value => console.log(label, value)
const range = x => from(Array(x).fill(0).map((_, k) => k + 1))

const bind = (base, f) => next
  base(data => f(data)(next))

// f x == just x >>= f
const first = _ => {
  const x = 3
  range(x)(log('first'))
  bind(just(x), range)(log('first*'))
}
// m == m >>= just
const second = _ => {
  const o = from([1, 2, 3])
  o(log('second'))
  bind(o, just)(log('second*'))
}
// m >>= (x => f(x) >>= h) == m >>= f >>= h
const third = _ => {
  const o = from([1, 2, 3])
  bind(o, x => bind(range(x), range))(log('third'))
  bind(bind(o, range), range)(log('third*'))
}