node-promisify

Convert callback function to a new function which returns a promise.

Function name and other own enumberable properties are preserved, as well as the execution context.

Custom promise can be used instead of the native.

Usage

var promisify = require('node-promisify');
promisify(function async(a, b, c, cb) {
    cb(null, d, e, f);
}, -1).then(function (results) {
    // results is [d, e, f]
});

pfn = promisify(fn, promise)

pfn = promisify(fn, argc)

pfn = promisify(fn, opts)

• fn: Function the async function

• opts: Object

  • promise: Function Promise constructor to be used instead of the native.
  • argc: Number The number of values should be delivered to the then callback, 1 by default. If argc is not 1, the callback will receive an array containing the exact number of resolved values. If specified as -1, all values are delivered.

Example

var promisify = require('..');
var glob = promisify(require('glob'));
var path = require('path');

glob('*.js', { cwd: path.join(__dirname, 'files') })
    .then(function (files) {
        console.log('promisish style:', files);
    });

glob('*.js', { cwd: path.join(__dirname, 'files') }, function (err, files) {
    console.log('original style:', files);
});

console.log('other methods:', glob.sync('*.js', { cwd: path.join(__dirname, 'files') }));

output:

⌘ node example/glob.js
other methods: [ 'a.js', 'b.js', 'c.js' ]
original style: [ 'a.js', 'b.js', 'c.js' ]
promisish style: [ 'a.js', 'b.js', 'c.js' ]