pify-proto

Promisify methods on the prototype of an object

• Exclusively for promisfying enumerable methods on a prototype
• Does not modify the original object prototype; returns a copy with a new prototype*
• Only include/exclude/multiArgs options (I don't need the others; always open to PRs)

* In order that the lib can operate normally if it uses any method internally (because it will be passing callbacks as per original method signature).

Credit goes to Sindre Sorhus and other contributors of pify, for which this is a fork. Thanks y'all!

Install

$ npm install --save pify-proto

Usage

const pify = require('pify-proto');

class SomeConstructor {
  constructor () {
    this.foo = 'bar'
  }
  
  baz (cb) {
    cb(null, this.foo)
  }
}

// promisify prototype of an object

const inst = pify(new SomeConstructor())

inst.baz().then(console.log.bind(console))
//=> 'foo'

API

pify(input, [promiseModule], [options])

Returns a new object with prototype methods on obj promisified.

input

Type: object

The object to promisify.

promiseModule

Type: function

Custom promise module to use instead of the native one.

Check out pinkie-promise if you need a tiny promise polyfill.

options

include

Type: array of (string|regex)

Methods in a module to promisify. Remaining methods will be left untouched.

exclude

Type: array of (string|regex) Default: [/.+Sync$/]

Methods in a module not to promisify. Methods with names ending with 'Sync' are excluded by default.

multiArgs

Type: boolean Default: false

By default, the promisified methods will only return the second argument from the callback, which works fine for most APIs. This option can be useful for modules like oauth with prototype methods that return multiple arguments. Turning this on will make it return an array of all arguments from the callback, excluding the error argument, instead of just the second argument.

const OAuth = require('oauth').OAuth;
const pify = require('pify-proto');

const oauth = pify(new OAuth(
    'http://blah',
    'http://blah',
    'blah blah'
), {multiArgs: true});

oauth.getOAuthRequestToken()
.then(result => {
	const [ oauth_token, oauth_secret ] = result;
});

Authors & License

pify was created by Sindre Sorhus.

pify-proto was created by Sam Gluck.

pify-proto contributors:

• Scott Donnelly (@sdd)

pify-proto is released under the MIT license.