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						- 
 - # thenify
 - 
 - [![NPM version][npm-image]][npm-url]
 - [![Build status][travis-image]][travis-url]
 - [![Test coverage][coveralls-image]][coveralls-url]
 - [![Dependency Status][david-image]][david-url]
 - [![License][license-image]][license-url]
 - [![Downloads][downloads-image]][downloads-url]
 - 
 - Promisify a callback-based function using [`any-promise`](https://github.com/kevinbeaty/any-promise).
 - 
 - - Preserves function names
 - - Uses a native promise implementation if available and tries to fall back to a promise implementation such as `bluebird`
 - - Converts multiple arguments from the callback into an `Array`, also support change the behavior by `options.multiArgs`
 - - Resulting function never deoptimizes
 - - Supports both callback and promise style
 - 
 - An added benefit is that `throw`n errors in that async function will be caught by the promise!
 - 
 - ## API
 - 
 - ### fn = thenify(fn, options)
 - 
 - Promisifies a function.
 - 
 - ### Options
 - 
 - `options` are optional.
 - 
 - - `options.withCallback` - support both callback and promise style, default to `false`.
 - - `options.multiArgs` - change the behavior when callback have multiple arguments. default to `true`.
 -   - `true` - converts multiple arguments to an array
 -   - `false`- always use the first argument
 -   - `Array` - converts multiple arguments to an object with keys provided in `options.multiArgs`
 - 
 - - Turn async functions into promises
 - 
 - ```js
 - var thenify = require('thenify');
 - 
 - var somethingAsync = thenify(function somethingAsync(a, b, c, callback) {
 -   callback(null, a, b, c);
 - });
 - ```
 - 
 - - Backward compatible with callback
 - 
 - ```js
 - var thenify = require('thenify');
 - 
 - var somethingAsync = thenify(function somethingAsync(a, b, c, callback) {
 -   callback(null, a, b, c);
 - }, { withCallback: true });
 - 
 - // somethingAsync(a, b, c).then(onFulfilled).catch(onRejected);
 - // somethingAsync(a, b, c, function () {});
 - ```
 - 
 - or use `thenify.withCallback()`
 - 
 - ```js
 - var thenify = require('thenify').withCallback;
 - 
 - var somethingAsync = thenify(function somethingAsync(a, b, c, callback) {
 -   callback(null, a, b, c);
 - });
 - 
 - // somethingAsync(a, b, c).then(onFulfilled).catch(onRejected);
 - // somethingAsync(a, b, c, function () {});
 - ```
 - 
 - - Always return the first argument in callback
 - 
 - ```js
 - var thenify = require('thenify');
 - 
 - var promise = thenify(function (callback) {
 -   callback(null, 1, 2, 3);
 - }, { multiArgs: false });
 - 
 - // promise().then(function onFulfilled(value) {
 - //   assert.equal(value, 1);
 - // });
 - ```
 - 
 - - Converts callback arguments to an object
 - 
 - ```js
 - var thenify = require('thenify');
 - 
 - var promise = thenify(function (callback) {
 -   callback(null, 1, 2, 3);
 - }, { multiArgs: [ 'one', 'tow', 'three' ] });
 - 
 - // promise().then(function onFulfilled(value) {
 - //   assert.deepEqual(value, {
 - //     one: 1,
 - //     tow: 2,
 - //     three: 3
 - //   });
 - // });
 - ```
 - 
 - [gitter-image]: https://badges.gitter.im/thenables/thenify.png
 - [gitter-url]: https://gitter.im/thenables/thenify
 - [npm-image]: https://img.shields.io/npm/v/thenify.svg?style=flat-square
 - [npm-url]: https://npmjs.org/package/thenify
 - [github-tag]: http://img.shields.io/github/tag/thenables/thenify.svg?style=flat-square
 - [github-url]: https://github.com/thenables/thenify/tags
 - [travis-image]: https://img.shields.io/travis/thenables/thenify.svg?style=flat-square
 - [travis-url]: https://travis-ci.org/thenables/thenify
 - [coveralls-image]: https://img.shields.io/coveralls/thenables/thenify.svg?style=flat-square
 - [coveralls-url]: https://coveralls.io/r/thenables/thenify
 - [david-image]: http://img.shields.io/david/thenables/thenify.svg?style=flat-square
 - [david-url]: https://david-dm.org/thenables/thenify
 - [license-image]: http://img.shields.io/npm/l/thenify.svg?style=flat-square
 - [license-url]: LICENSE
 - [downloads-image]: http://img.shields.io/npm/dm/thenify.svg?style=flat-square
 - [downloads-url]: https://npmjs.org/package/thenify
 
 
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