then

make it painless to adapt between callbacks and promises

usage

then is like a magic portal to warp between Promised land and the firey depths of Callback hell.

var then = require('th')
var fs = require('fs')

fs.readFile('./tmp', then())
then(function (file) {
  console.log('file')
}, function (err) {
  console.log('errors!', err)
})

// although you may want to be using streaming file methods, anyhow

When we invoke then() the first time, it creates a callback to give to fs.readFile. When we call it the next time, it's like a Promises/A+ then method.

Importantly, there are times when we want to go back from a chain of promises to a callback:

function (err, nextCb) {
  if (err) { return nextCb(err) }
  var promise = myPromise()
    .then(someStep)
    .then(oneMoreThing)

  then.callback(promise, nextCb)
}

api

then : () => Promise | (resolved: Function, rejected: Function) => Promise

See usage note above for behavior.

then.callback(Promise<T>, Callback<T>) => void

Registers the callback as a handler for promise resolve and reject events.

installation

$ npm install th

running the tests

From package root:

$ npm install
$ npm test

contributors

• jden [email protected]

license

MIT. (c) MMXIII AgileMD http://agilemd.com