eventuate-next

Act upon the next produced value of an eventuate

example

var eventuate = require('eventuate-core'),
    next      = require('eventuate-next')

var service = {
    login: eventuate()
}

// with a callback
next(service.login, function (err, user) {
    if (err) console.error(err)
    console.log(user.name + ' logged in!')
})

// or with a promise
next(service.login).then(function (user) {
    console.log(user.name + ' logged in!')
}).catch(console.error)


service.login.produce({ name: 'John' }) // will be logged (twice)
service.login.produce({ name: 'Tim' }) // will not be logged

api

var next = require('eventuate-next')

next(eventuate [, cb])

next requires a (non-basic) eventuate as it's 1st argument, and optionally accepts an error-first callback, cb, as a 2nd argument. The next function returns a Promise. When the given eventuate produces it's next value, the Promise will resolve with the value. If a callback was provides, it will be executed with a falsy error and the value.

If, while next is waiting on a value to be produces, the consumer that next attaches to the eventuate is removed, or the eventuate is destroyed, then the Promise will be rejected with a NextCancelledError (see below). If a callback was provided, it will be executed with the NextCancelledError. The error object will have a property of destroyed which will be a boolean, and can be used to determine if the eventuate was destroyed, or if an action removed the next consumer while leaving the eventuate in-tact.

errors

var errors = require('eventuate-next/errors')

errors.NextCancelledError

Constructor of error supplied to callback or Promise rejection in the event the next consumer is removed or the eventuate is destroyed before the eventuate produces a value.

install

With npm do:

npm install --save eventuate-next

testing

npm test

Or to run tests in phantom: npm run phantom

coverage

npm run view-cover

This will output a textual coverage report.

npm run open-cover

This will open an HTML coverage report in the default browser.