Airat Zhanshuakov codev0

@kangax's ES6 quiz, explained

@kangax created a new interesting quiz, this time devoted to ES6 (aka ES2015). I found this quiz very interesting and quite hard (made myself 3 mistakes on first pass).

Here we go with the explanations:

Question 1:

(function(x, f = () =&gt; x) {

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

Install OSX Parallels version 10/11/12/13 tools on Ubuntu server guest

Have tested these instructions successfully under Ubuntu 16.04LTS and 14.04LTS.

Create Ubuntu server instance under Parallels (obviously).
Start VM, goto Actions - Install Parallels Tools... to mount the ISO image.
- Note: if this fails, or updating tools for an existing guest you can do the following:
- Goto Devices > CD/DVD 1 > Connect Image....
- Select the following ISO image: /Applications/Parallels Desktop/Contents/Resources/Tools/prl-tools-lin.iso.
- This will mount the tools CD image.

Styling native elements

Native HTML controls are a challenge to style. You can style any element in the web platform that uses Shadow DOM with a pseudo element ::pseudo-element or the /deep/ path selector.

video::webkit-media-controls-timeline {
  background-color: lime;
}

video /deep/ input[type=range] {

Commit Message Conventions

These rules are adopted from the AngularJS commit conventions.

Goals
Generating CHANGELOG.md
- Recognizing unimportant commits
- Provide more information when browsing the history
Format of the commit message
Subject line

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.

	import express from "express";

	/**
	* Takes a route handling function and returns a function
	* that wraps it after first checking that the strings in
	* `reserved` are not part of `req.body`. Used for ensuring
	* create and update requests do not overwrite server-generated
	* values.
	*/
	function checkReservedParams(routeHandler, ...reserved) {

	var express = require('express');
	var cookieParser = require('cookie-parser');
	var session = require('express-session');
	var flash = require('express-flash');
	var handlebars = require('express-handlebars')

	var app = express();
	var sessionStore = new session.MemoryStore;

	// View Engines

	/*
	********************************************************************************
	Golang - Asterisk and Ampersand Cheatsheet
	********************************************************************************

	Also available at: https://play.golang.org/p/lNpnS9j1ma

	Allowed:
	--------
	p := Person{"Steve", 28} stores the value