th.en - make it painless to adapt between callbacks and promises
npm install ththen is like a magic portal to warp between Promised land and the firey depths of Callback hell.
``js
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:
`js
function (err, nextCb) {
if (err) { return nextCb(err) }
var promise = myPromise()
.then(someStep)
.then(oneMoreThing)
then.callback(promise, nextCb)
}
`
as a handler for promise resolve and reject` events.$ npm install th
From package root:
$ npm install
$ npm test
- jden