const promisify = require('bluebird').promisify
  const from = require('rxjs').from
  const isTrue = require('callbaxx').isTrue

  const isTrueAsync = promisify(isTrue)
  const makeIsTrueSource = val => from(isTrueAsync(val))

  const source = makeIsTrueSource(true)

  source.subscribe(console.log, console.error)