Voucher

Promises is coming in the new ES6 spec. This excellent article should convince you to use it.

A lot of libraries today still takes callback arguments rather than returning promises. Voucher will wrap the calls and give you a promise to work with. Easy.

Install

npm install voucher

Examples

$3

``javascript
var crypto = require('crypto');
var voucher = require('voucher');

voucher(crypto.pseudoRandomBytes, 12).then(function(randomBytesBuffer) {
console.log(randomBytesBuffer.toString('hex'));
});
`

`javascript
var fs = require('fs');
var voucher = require('voucher');

voucher(fs.readFile, '/etc/passwd', { encoding: 'utf8' }).then(function(content) {
console.log(content); // Logs the contents of '/etc/passwd'
}).catch(function(error) {
console.log('Something went wrong when reading file:', error);
});
`

Requirements


* The callback argument of the function specified __must be the last argument__.
* The callback __must__ be invoked with error as its first argument.

All NodeJS native functions works well. For instance, fs.readFile takes a
filename parameter, then an optional options object and then the callback function.
The callback function receives two parameters, first err` which indicates if
anything went wrong, then the result of the readFile operation.