81 lines
2.6 KiB
Markdown
81 lines
2.6 KiB
Markdown
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# EE First
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[![NPM version][npm-image]][npm-url]
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[![Build status][travis-image]][travis-url]
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[![Test coverage][coveralls-image]][coveralls-url]
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[![License][license-image]][license-url]
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[![Downloads][downloads-image]][downloads-url]
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[![Gittip][gittip-image]][gittip-url]
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Get the first event in a set of event emitters and event pairs,
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then clean up after itself.
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## Install
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```sh
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$ npm install ee-first
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```
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## API
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```js
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var first = require('ee-first')
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```
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### first(arr, listener)
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Invoke `listener` on the first event from the list specified in `arr`. `arr` is
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an array of arrays, with each array in the format `[ee, ...event]`. `listener`
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will be called only once, the first time any of the given events are emitted. If
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`error` is one of the listened events, then if that fires first, the `listener`
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will be given the `err` argument.
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The `listener` is invoked as `listener(err, ee, event, args)`, where `err` is the
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first argument emitted from an `error` event, if applicable; `ee` is the event
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emitter that fired; `event` is the string event name that fired; and `args` is an
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array of the arguments that were emitted on the event.
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```js
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var ee1 = new EventEmitter()
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var ee2 = new EventEmitter()
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first([
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[ee1, 'close', 'end', 'error'],
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[ee2, 'error']
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], function (err, ee, event, args) {
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// listener invoked
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})
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```
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#### .cancel()
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The group of listeners can be cancelled before being invoked and have all the event
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listeners removed from the underlying event emitters.
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```js
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var thunk = first([
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[ee1, 'close', 'end', 'error'],
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[ee2, 'error']
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], function (err, ee, event, args) {
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// listener invoked
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})
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// cancel and clean up
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thunk.cancel()
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```
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[npm-image]: https://img.shields.io/npm/v/ee-first.svg?style=flat-square
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[npm-url]: https://npmjs.org/package/ee-first
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[github-tag]: http://img.shields.io/github/tag/jonathanong/ee-first.svg?style=flat-square
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[github-url]: https://github.com/jonathanong/ee-first/tags
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[travis-image]: https://img.shields.io/travis/jonathanong/ee-first.svg?style=flat-square
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[travis-url]: https://travis-ci.org/jonathanong/ee-first
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[coveralls-image]: https://img.shields.io/coveralls/jonathanong/ee-first.svg?style=flat-square
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[coveralls-url]: https://coveralls.io/r/jonathanong/ee-first?branch=master
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[license-image]: http://img.shields.io/npm/l/ee-first.svg?style=flat-square
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[license-url]: LICENSE.md
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[downloads-image]: http://img.shields.io/npm/dm/ee-first.svg?style=flat-square
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[downloads-url]: https://npmjs.org/package/ee-first
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[gittip-image]: https://img.shields.io/gittip/jonathanong.svg?style=flat-square
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[gittip-url]: https://www.gittip.com/jonathanong/
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