Michael Stillwell ithinkihaveacat

Comparison of two different approaches to structuring code that uses Promises.

Version using .then(), from Complex task dependencies:

files.getLastTwoVersions(filename)
    .then(function(items) {
        return [versions.get(items.last), 
                versions.get(items.previous)];
 })

Compared to the .then() style, this approach:

Looks almost identical to the non-Promise version--you end up with imperative code, just like the non-Promise equivalent, instead of long .then() chains. (Unfortunately you do still need to use .catch() to handle exceptions/rejections.)
Supports functions of multiple arguments, including functions where some of the arguments are Promises, and some not.
Works by transforming a normal-looking function--if you have a pure function that is not asynchronous, with primitive types as arguments and a primitive type as a return value, you don't even need to know that Promises are involved.
With a helper function, it also supports fairly natural-looking method calls where the arguments and return v

	function F(fn) {
	return function (/* arguments */) {
	var args = [this].concat(Array.prototype.slice.call(arguments));
	return new Promise(function (resolve, reject) {
	Promise.all(args).then(function (/* arguments */) {
	try {
	Promise.resolve(
	fn.apply(arguments[0].shift(), arguments[0])
	).then(resolve, reject);
	} catch (e) {

	#!/bin/bash

	# NOTE: This (sadly) doesn't work in all situations. See
	# https://github.com/composer/composer/pull/1083
	# for discussion of some alternatives.

	# Checks whether composer.json has changed after checkout, in which
	# case you probably need to run 'composer install'.
	#
	# INSTALLATION

	<?php

	array (
	0 =>
	array (
	'file' => '/usr/share/php/BBC/Controller/Plugin/CacheControl.php',
	'line' => 59,
	'function' => 'rawstack',
	),
	1 =>

	<?php

	/**
	* Similar to print_r(), except that it writes to /tmp/rawlog.log. This function is
	* intended for debugging, where you want to be absolutely sure that your output
	* is not being captured or buffered or otherwise interfered with.
	*
	* One good way to ensure this is always available is to use the auto_prepend_file
	* php.ini setting.
	*/

	function onChild(child, event, callback) {
	child.on('message', (function (args) {
	if (args[0] === event) {
	callback.apply(null, Array.prototype.slice.call(args, 1));
	}
	}));
	}

	function emitChild(/* child, event, [arg1], [arg2], [...] */) {
	var args = Array.prototype.slice.call(arguments);

	# Vagrantfile snippet to check that apache_server_name resolves to vm_ip (i.e.
	# assuming that the rest of the Vagrantfile configures a VM in this way).

	apache_server_name = "myproject.local"
	vm_ip = "192.168.33.111"

	begin
	res = Socket::getaddrinfo(apache_server_name, nil, Socket::AF_INET)
	rescue SocketError => e
	# s doesn't resolve to anything at all

	mycallback({
	"count": 10,
	"value": {
	"title": "test",
	"description": "Pipes Output",
	"link": "http://pipes.yahoo.com/pipes/pipe.info?_id=bc115235e32da3e0f6db46cd7a159a01",
	"pubDate": "Sun, 12 Aug 2012 21:00:39 +0000",
	"generator": "http://pipes.yahoo.com/pipes/",
	"callback": "mycallback",
	"items": [