proback.js - dependency-free very minimal helper for APIs with Promise/callback dual design

========

proback.js is an extremely tiny helper library to help the creation of APIs where functions are aimed to enable Promise-based and callback-based design as well.

Usage Rules

Usage

Command line:

npm install proback.js --save

In JS code:

	var Proback = require('proback.js');
	...
	// your service. If callback is present, works as expected, If not, promise will be provided.
	function yourService( data, callback ){
		new Promise( function (resolve, reject) {
			//some callback is needed?
			object.fnCallWithCallback( data, Proback.handler( null, resolve, reject ) )
		}).then( function (res) {
			expect(res).to.equal('Done.')
			done()
		})
	}

	var Proback = require('proback.js');
	...
	// your service. If callback is present, works as expected, If not, promise will be provided.
	function yourService( data, callback ){
		return new Promise( function (resolve, reject) {
			//some callback is needed?
			object.fnCallWithCallback( data, function (err, res) {
				if (err) return Proback.rejecter(err, null, reject)
				// some operation
				return Proback.resolver(res, null, resolve)
			} )
		}).then( function (res) {
			expect(res).to.equal('Done.')
			done()
		})
	}

Rules

• quicker ( res, callback ) Defines a simple promise to send a result through the optional callback as well

• thrower ( err, callback ) Defines a simple promise to throw an error through the optional callback as well

• syncAll (promises) Performes all promises in order

• forAll ( promises, callback, defaultRes ) Performes all promises and channel the result to the given callback

• handler ( callback, resolve, reject ) Defines a callback function, which will use the passed opional callback and promise functions to channel the results

• returner ( err, res, callback, resolve, reject ) Error mades it mark the error through the optional callback and the optional reject function or send the result back to the optional callback or the optional resolve function

• resolver (res, callback, resolve) Sends a result through the optional callback and the optional reject function

• rejecter (err, callback, reject) Marks an error through the optional callback and the optional reject function