th/index.js

th.en - make it painless to adapt between callbacks and promises

var Q = require('q')

var next = null
function then (resolved, rejected) {
  return next ? pop(resolved, rejected) : push()
}

function push() {
  next = Q.defer()
  return function (err, val) {
    if (err) {
      next.reject(err)
      return
    }
    next.resolve(val)
  }
}

function pop(resolved, rejected) {
  var _next = next
  next = null
  return _next.promise.then(resolved, rejected)
}

then.callback = function callback(promise, cb) {
  promise.then(function (val) {
    cb(null, val)
  }, function (err) {
    cb(err)
  })
}

module.exports = then
module.exports.en = then