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80 lines
2.6 KiB
80 lines
2.6 KiB
# 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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