20200630.js

;(function () {
  const { S, F } = require ('./src/utils/sanctuary') ()
  const control = F.coalesce (_ => S.Nothing) (S.Just)
  const fut = F.go (function * () {
    // const book1 = yield F.resolve ('Python')
    const book1 = yield control (F.reject ('?network error'))
    const book2 = yield control (F.resolve ('JavaScript'))
    return {
      book1,
      book2,
    }
  })
  const happy = x => console.log ('resolved:', x)
  const unhappy = x => console.error ('rejected:', x)
  F.fork (unhappy) (happy) (fut)
}) ()