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Write procedural style code that runs asynchronously. It may look synchronous, but it's not!

Basic Example

var Bernhard = require('procedural-async');
var models = require('./models');

	try {
		// Not needed now, don't block.
		var current_user = models.User.retrieveByName(req.session.username);
		var genre = models.Genre.retrieveByName(req.query.genre);
		// Will wait on results.
		var book_results ={genre:});
		var favorite_book_ids = current_user.retrieveFavoriteBookIds();
		var response_data ={
			return {
				title: book.title,
				author: book.retrieveAuthor().name,
				is_favorite: favorite_book_ids.indexOf( > -1
	} catch (e) {
		return next(e);

Full Example Code

Example Using caolan's (excellent) async


  • Fully asynchronous, with the option to be synchronous
  • Execute asynchronous calls immediately, but wait for the results only at the time you need them
  • Allows for try/catch error handling
  • instances are subclasses of any class you like
  • Easy to read and write

How it Works

Under the hood, node-procedural-async uses a combination of Proxies and node-fibers. When you call Bernhard.generate, a proxy class is dynamically generated, instanciated and returned. All calls to the proxy will yield until whatever asynchronous task you started has completed. The asynchronous/synchronous magic comes from fibers, so you must write your procedural-async code inside a function that you pass to Bernhard.async.


The current version requires node.js v0.11.4 and an experimental untagged version of node-fibers.


Setting Up Your Asynchronous Code


Returns an instance that derives from Class. You should return this instance from your asynchronous function immediately.

instance.callback([err, [result]])

Call this on the instance you got from Bernhard.generate when your asynchronous function has completed.

Using Your Asynchronous Code


Put all your procedural-async code inside a function that you pass to this method. Inside this function, you can try/catch any errors.


This library was developed by Ben Kovacevich, David Fenster, and Carlos Gomez at Shutterstock


This library would not be possible without Marcel Laverdet's outstanding fibers library.


MIT © 2013-2017 Shutterstock Images, LLC

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