promise-shim

For when your promise libraries promisify method just won't cut it!

Promises are awesome, but sometimes you need to use API's that just do not support them. Most promise libraries provide a promisify method to convert API's that take node style callback, but they do not work in every situation. promise-shim helps fill the gap.

Install

$ npm install --save promise-shim

Usage

// You need to provide a Promise implementation:
var promiseShim = require('promise-shim')(PromiseConstructor);
 
// or if global.Promise is already a valid promise constructor:
var promiseShim = require('promise-shim')();
 
var promise = promiseShim(function (cb) {
  cb(someError); // rejects the promise
  cb(null, someValue); // resolves the promise
});

You can pass arguments to your function. Really helpful when using bind:

 
var myService = promiseShim.bind(null, function(cb, a, b) {
  console.log(a); // => 'foo-a';
  console.log(b); // => 'foo-b';
  cb(null, a + b);
});
 
// myService is now a reusable function that returns a promise:
 
myService('foo-a', 'foo-b').then(...);

Note: Always check your Promise libraries options for "promisification", you will only need promise-shim in specific instances.

Related:

• promise-resolver

License

MIT © James Talmage