Treat low level async functions as promises

async-to-promise.js

var slice = Function.prototype.bind.bind(Array.prototype.slice);

var p = function (fn, args) {
	var d = defer();
	fn.apply(this, slice(arguments, 1).concat(function (error, result) {
		d.resolve((error == null) ? result : error);
	}));
	return d.promise;
};


p(fs.stat, '/path').then(function (stat) {
	// ...
});

p(fs.readFile, '/path', 'utf-8').then(function (text) {
	// ...
});

p(path.exists, '/path').then(function (exists) {
	// ...
});