| 1 | # EE First
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| 2 |
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| 3 | [![NPM version][npm-image]][npm-url]
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| 4 | [![Build status][travis-image]][travis-url]
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| 5 | [![Test coverage][coveralls-image]][coveralls-url]
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| 6 | [![License][license-image]][license-url]
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| 7 | [![Downloads][downloads-image]][downloads-url]
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| 8 | [![Gittip][gittip-image]][gittip-url]
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| 9 |
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| 10 | Get the first event in a set of event emitters and event pairs,
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| 11 | then clean up after itself.
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| 12 |
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| 13 | ## Install
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| 14 |
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| 15 | ```sh
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| 16 | $ npm install ee-first
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| 17 | ```
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| 18 |
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| 19 | ## API
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| 20 |
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| 21 | ```js
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| 22 | var first = require('ee-first')
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| 23 | ```
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| 24 |
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| 25 | ### first(arr, listener)
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| 26 |
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| 27 | Invoke `listener` on the first event from the list specified in `arr`. `arr` is
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| 28 | an array of arrays, with each array in the format `[ee, ...event]`. `listener`
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| 29 | will be called only once, the first time any of the given events are emitted. If
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| 30 | `error` is one of the listened events, then if that fires first, the `listener`
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| 31 | will be given the `err` argument.
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| 32 |
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| 33 | The `listener` is invoked as `listener(err, ee, event, args)`, where `err` is the
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| 34 | first argument emitted from an `error` event, if applicable; `ee` is the event
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| 35 | emitter that fired; `event` is the string event name that fired; and `args` is an
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| 36 | array of the arguments that were emitted on the event.
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| 37 |
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| 38 | ```js
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| 39 | var ee1 = new EventEmitter()
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| 40 | var ee2 = new EventEmitter()
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| 41 |
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| 42 | first([
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| 43 | [ee1, 'close', 'end', 'error'],
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| 44 | [ee2, 'error']
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| 45 | ], function (err, ee, event, args) {
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| 46 | // listener invoked
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| 47 | })
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| 48 | ```
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| 49 |
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| 50 | #### .cancel()
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| 51 |
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| 52 | The group of listeners can be cancelled before being invoked and have all the event
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| 53 | listeners removed from the underlying event emitters.
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| 54 |
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| 55 | ```js
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| 56 | var thunk = first([
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| 57 | [ee1, 'close', 'end', 'error'],
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| 58 | [ee2, 'error']
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| 59 | ], function (err, ee, event, args) {
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| 60 | // listener invoked
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| 61 | })
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| 62 |
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| 63 | // cancel and clean up
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| 64 | thunk.cancel()
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| 65 | ```
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| 66 |
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| 67 | [npm-image]: https://img.shields.io/npm/v/ee-first.svg?style=flat-square
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| 68 | [npm-url]: https://npmjs.org/package/ee-first
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| 69 | [github-tag]: http://img.shields.io/github/tag/jonathanong/ee-first.svg?style=flat-square
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| 70 | [github-url]: https://github.com/jonathanong/ee-first/tags
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| 71 | [travis-image]: https://img.shields.io/travis/jonathanong/ee-first.svg?style=flat-square
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| 72 | [travis-url]: https://travis-ci.org/jonathanong/ee-first
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| 73 | [coveralls-image]: https://img.shields.io/coveralls/jonathanong/ee-first.svg?style=flat-square
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| 74 | [coveralls-url]: https://coveralls.io/r/jonathanong/ee-first?branch=master
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| 75 | [license-image]: http://img.shields.io/npm/l/ee-first.svg?style=flat-square
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| 76 | [license-url]: LICENSE.md
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| 77 | [downloads-image]: http://img.shields.io/npm/dm/ee-first.svg?style=flat-square
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| 78 | [downloads-url]: https://npmjs.org/package/ee-first
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| 79 | [gittip-image]: https://img.shields.io/gittip/jonathanong.svg?style=flat-square
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| 80 | [gittip-url]: https://www.gittip.com/jonathanong/
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