Ching-Han Ho chinghanho

PostgreSQL is Enough

Background and Cron Jobs

Not all random values are created equal - for security-related code, you need a specific kind of random value.

A summary of this article, if you don't want to read the entire thing:

Don't use Math.random(). There are extremely few cases where Math.random() is the right answer. Don't use it, unless you've read this entire article, and determined that it's necessary for your case.
Don't use crypto.getRandomBytes directly. While it's a CSPRNG, it's easy to bias the result when 'transforming' it, such that the output becomes more predictable.
If you want to generate random tokens or API keys: Use uuid, specifically the uuid.v4() method. Avoid node-uuid - it's not the same package, and doesn't produce reliably secure random values.
If you want to generate random numbers in a range: Use random-number-csprng.

You should seriously consider reading the entire article, though - it's

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

Encoding Video

Installing

Install FFmpeg with homebrew. You'll need to install it with a couple flags for webm and the AAC audio codec.

brew install ffmpeg --with-libvpx --with-libvorbis --with-fdk-aac --with-opus

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

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.

	<!DOCTYPE html>
	<meta charset='utf-8'>
	<style>

	body{
	margin: 0px;
	}

	path{
	stroke: black;


	// convert three r,g,b integers (each 0-255) to a single decimal integer (something between 0 and ~16m)
	function colourToNumber(r, g, b) {
	return (r << 16) + (g << 8) + (b);
	}

	// convert it back again (to a string)
	function numberToColour(number) {
	const r = (number & 0xff0000) >> 16;
	const g = (number & 0x00ff00) >> 8;

	/* VT100 terminal reset (<ESC>c) */

	console.log('\033c');

	/* numbers comparations */

	> '2' == 2
	true

	> '2' === 2

	/* bling.js */
	window.$ = document.querySelector.bind(document);
	window.$$ = document.querySelectorAll.bind(document);
	Node.prototype.on = window.on = function(name, fn) { this.addEventListener(name, fn); };
	NodeList.prototype.__proto__ = Array.prototype;
	NodeList.prototype.on = function(name, fn) { this.forEach((elem) => elem.on(name, fn)); };

	#!/bin/bash

	### USAGE
	###
	### ./ElasticSearch.sh 1.7 will install Elasticsearch 1.7
	### ./ElasticSearch.sh will fail because no version was specified (exit code 1)
	###
	### CLI options Contributed by @janpieper
	### Check http://www.elasticsearch.org/download/ for latest version of ElasticSearch