afterward


Execute an error-first callback upon resolution or rejection of a promise, and return the promise.

This makes it easier to write functions that support both callback and promise based async patterns.

example

``javascript
var afterward = require('afterward'),
Promise = require('promise-polyfill')

function greet (name, cb) {
var prom = new Promise(function (resolve) {
setTimeout(resolve.bind(undefined, 'greetings ' + name), 100)
})
return afterward(prom, cb)
}

// we can now use our fancy function either way...
// with a callback:
greet('jason', function (err, msg) {
if (err) return console.error(err)
console.log(msg)
})

// or a promise
greet('gege').then(console.log).catch(console.error)
`

api

`javascript
var afterward = require('afterward')
`

$3

Upon resolution or rejection of the promise prom, execute the optional error-first style callback cb. The promise prom is returned.

$3

`javascript
var UnknownError = require('afterward/errors').UnknownError
`

#### UnknownError

The constructor function of the Error object provided to callback cb when the Promise prom is rejected with no argument.

testing

npm test [--dot | --spec] [--phantom] [--grep=pattern]

Specifying --dot or --spec will change the output from the default TAP style.
Specifying --phantom will cause the tests to run in the headless phantom browser instead of node.
Specifying --grep will only run the test files that match the given pattern.

$3

npm run browser-test

This will run the tests in all browsers (specified in .zuul.yml). Be sure to educate zuul first.

$3

npm run coverage [--html]

This will output a textual coverage report. Including --html` will also open
an HTML coverage report in the default browser.