Tiny Node Promisify

Minimalist library to promisify functions expecting node-style callbacks.

Install

npm install tiny-promisify

Usage

Given a fn that uses the node-style callbacks, expecting a callback as the last parameter and this callback expecting an err as the first parameter, you can obtain a new function that return promises as follows:

var promisify = require('tiny-promisify');

function fn (args, callback) {
  // fn code here...
  callback(err, results);
}

var fnAsync = promisify(fn);
fnAsync(args).then(function (result) {
  // your code here...
}).catch(function (err) {
  // handle error here...
});

API

promisify(fn, [options])

• fn is a function that receives a callback as the last. argument. The callback will receive an err object as the first argument.
• options is an optional object having the following properties:
  • multiArgs set to true will make the promise resolve to an array containing all the parameters passed to the callback. Otherwise, only the first non-error parameter is passed to the promise success callback. Defaults to false.
  • context is the object uses as this when calling fn. Defaults to {}.

Returns a new function that wraps fn in a promise.

Notes

The module uses Babel's polyfills for Promise and Object.assign() when not found in the current execution environment.

You can require the ES2015 version of the lib by specifying the source file: require('tiny-promisify/lib').

License

WTFPL