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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