Promise Example

promise_example.js

// npm install promised-io
var promised = require('promised-io/promise');

 // all of these async methods return an instance of promised.Promise
var filePromise = getFile('/foo.html')
  , databasePromise = getDatabaseRecord('users/bentruyman')
  , websocketPromise = establishWebsocketConnection();

promised.all([filePromise, databasePromise, websocketPromise], function (arrayOfResolvedData) {
	// all promises have been resolved
});

function getFile(filename) {
	var promise = new promised.Promise();

	getFileFromSomewhereAsynchronously(filename, function (data) {
		promise.resolve(data);
	});

	return promise;
}

// etc...