José Pedro Dias JosePedroDias

The introduction to Reactive Programming you've been missing

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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Powerlevel10k

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

This article has been given a more permanent home on my blog. Also, since it was first written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.

You're Missing the Point of Promises

Promises are a software abstraction that makes working with asynchronous operations much more pleasant. In the most basic definition, your code will move from continuation-passing style:

getTweetsFor("domenic", function (err, results) {
 // the rest of your code goes here.

	var listToArr = function(lst) {
	var l = lst.length;
	var arr = new Array(l); // optimizable *list-to-array
	for (var i = 0; i < l; ++i) {
	arr[i] = lst[i];
	}
	return arr;
	};

	var ctx = this; // this can be skipped if you don't care about the context

	var argsL = arguments.length;
	var args = new Array(argsL); // optimizable arguments-to-array
	for(var i = 0; i < argsL; ++i) {
	args[i] = arguments[i];
	}

	var removeCycles = function(o) {
	var seen = [];

	var s = JSON.stringify(o, function(k, v) {
	if (v !== null && typeof v === 'object') {
	if (seen.indexOf(v) !== -1) {
	//return;
	v = '[removed]';
	}
	else {

	var os = require('os');

	var getMyIPs = function() {
	var ips = {};
	var ifaces = os.networkInterfaces();

	var onDetails = function(details) {
	if (details.family === 'IPv4') {
	ips[ dev ] = details.address;
	}

	#!/usr/bin/env phantomjs

	var system = require('system');
	var text = encodeURIComponent(system.stdin.read());
	var url = "http://translate.google.com/#auto/en/" + text;

	var page = require('webpage').create();
	page.settings.userAgent = 'Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:13.0) Gecko/20100101 Firefox/13.0';

	page.onConsoleMessage = function (msg) {

	// Here’s a 100% deterministic alternative to `Math.random`. Google’s V8 and
	// Octane benchmark suites use this to ensure predictable results.

	Math.random = (function() {
	var seed = 0x2F6E2B1;
	return function() {
	// Robert Jenkins’ 32 bit integer hash function
	seed = ((seed + 0x7ED55D16) + (seed << 12)) & 0xFFFFFFFF;
	seed = ((seed ^ 0xC761C23C) ^ (seed >>> 19)) & 0xFFFFFFFF;
	seed = ((seed + 0x165667B1) + (seed << 5)) & 0xFFFFFFFF;