README.md (2617B)
1 # EE First 2 3 [![NPM version][npm-image]][npm-url] 4 [![Build status][travis-image]][travis-url] 5 [![Test coverage][coveralls-image]][coveralls-url] 6 [![License][license-image]][license-url] 7 [![Downloads][downloads-image]][downloads-url] 8 [![Gittip][gittip-image]][gittip-url] 9 10 Get the first event in a set of event emitters and event pairs, 11 then clean up after itself. 12 13 ## Install 14 15 ```sh 16 $ npm install ee-first 17 ``` 18 19 ## API 20 21 ```js 22 var first = require('ee-first') 23 ``` 24 25 ### first(arr, listener) 26 27 Invoke `listener` on the first event from the list specified in `arr`. `arr` is 28 an array of arrays, with each array in the format `[ee, ...event]`. `listener` 29 will be called only once, the first time any of the given events are emitted. If 30 `error` is one of the listened events, then if that fires first, the `listener` 31 will be given the `err` argument. 32 33 The `listener` is invoked as `listener(err, ee, event, args)`, where `err` is the 34 first argument emitted from an `error` event, if applicable; `ee` is the event 35 emitter that fired; `event` is the string event name that fired; and `args` is an 36 array of the arguments that were emitted on the event. 37 38 ```js 39 var ee1 = new EventEmitter() 40 var ee2 = new EventEmitter() 41 42 first([ 43 [ee1, 'close', 'end', 'error'], 44 [ee2, 'error'] 45 ], function (err, ee, event, args) { 46 // listener invoked 47 }) 48 ``` 49 50 #### .cancel() 51 52 The group of listeners can be cancelled before being invoked and have all the event 53 listeners removed from the underlying event emitters. 54 55 ```js 56 var thunk = first([ 57 [ee1, 'close', 'end', 'error'], 58 [ee2, 'error'] 59 ], function (err, ee, event, args) { 60 // listener invoked 61 }) 62 63 // cancel and clean up 64 thunk.cancel() 65 ``` 66 67 [npm-image]: https://img.shields.io/npm/v/ee-first.svg?style=flat-square 68 [npm-url]: https://npmjs.org/package/ee-first 69 [github-tag]: http://img.shields.io/github/tag/jonathanong/ee-first.svg?style=flat-square 70 [github-url]: https://github.com/jonathanong/ee-first/tags 71 [travis-image]: https://img.shields.io/travis/jonathanong/ee-first.svg?style=flat-square 72 [travis-url]: https://travis-ci.org/jonathanong/ee-first 73 [coveralls-image]: https://img.shields.io/coveralls/jonathanong/ee-first.svg?style=flat-square 74 [coveralls-url]: https://coveralls.io/r/jonathanong/ee-first?branch=master 75 [license-image]: http://img.shields.io/npm/l/ee-first.svg?style=flat-square 76 [license-url]: LICENSE.md 77 [downloads-image]: http://img.shields.io/npm/dm/ee-first.svg?style=flat-square 78 [downloads-url]: https://npmjs.org/package/ee-first 79 [gittip-image]: https://img.shields.io/gittip/jonathanong.svg?style=flat-square 80 [gittip-url]: https://www.gittip.com/jonathanong/