This Week in JavaScript - 15 November 2015

[chrisofarabia]

Hello and welcome to ‘This Week in JavaScript’ — another curated collection of links relating to what’s new and exciting in the world of JavaScript. The complete list is tagged jsweekly. (Don’t forget to check out our weekly .NET and front end roundups too!)

And now for this week’s finds …

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Getting started

• JavaScript Fundamentals: Assignment Operators - Compound assignment operators can be thought of as simple shortcuts to mathematical expressions; Dudley Storey explains.
• Part 3: An Intro to Functional Programming Concepts in JavaScript - Part 3 looks at pointed functors and introduces new functors to enable us to elegantly handle errors in our function compositions.

Learning more

• Recipes for Randomness in JavaScript - Dudley Storey shows a variety of JS code recipes for randomising numbers
• An Overview of JavaScript Templating Engines - JavaScript templates are a method of separating HTML structure from the content contained within. Here, Jamie Shields shows how they can be used.
• 20+ Docs and Guides for Front-end Developers (No. 6) - Louis Lazaris gives us his sixth installment of the Docs and Guides series
• Improved Ajax Techniques for WordPress: Object-Oriented Programming - Tom McFarlin revisits the topic of working with Ajax in WordPress
• Face Proximity Detection with JavaScript - Peter Bengtsson shows you how to build a video booth feature

ES6

• ECMAScript 6 Cheatsheet - Everything about the latest version of the ECMAScript (JavaScript) standard
• Using ES6 and ES7 in the Browser, with Babel 6 and Webpack - Part of The Complete Guide to ES6 with Babel 6 series
• The Six Things You Need To Know About Babel 6 - Get yourself up to speed, with this brief list of the six most important changes.

##ES7

• What’s in ECMAScript 2016 (ES7)? - Dr. Axel Rauschmayer describes the details of the new release process, along with four features that will probably be in ECMAScript 2016.

##ReactJS

• react-relay - The framework for building data-driven React applications moves up to v0.5.0
• React JS Tutorial for Beginners – Part 1 - A video-based introduction to ReactJS
• reactphp/promise - A lightweight implementation of CommonJS Promises/A for PHP

Libraries

• Web Playground - An Enjoyable Playground for HTML, JavaScript and CSS
• Revealing Elements with scrollReveal.js - Aurelio De Rosa takes a look at scrollReveal, a JavaScript library dedicated to creating animations.
• How to use PostCSS in Meteor - What’s so special about PostCSS and why is everyone are talking about it? Julian Ćwirko tells you why it’s awesome and how you can use it with Meteor.

Frameworks

• Highlights from AngularConnect 2015 - A nicely summarised view of October’s European Angular Conference 2015
• Microsoft + Node.js Guidelines - The start of an ongoing conversation on how we can improve the Node.js experience on Microsoft platforms.
• AngularJS’ Internals In Depth - Part 2 of Nicolas Bevacqua’s treatment of AngularJS’ Internals
• Creating Components in Angular 2 with Typescript and ES5 - Thomas Greco takes you through the process of building a component in Angular 2 from start to finish.
  ##Everything Else
• Codepen Tic Tac Toe in JS - Want a little time out? At least it will look like you’re working

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For more links like this and to keep up-to-date with the latest goings on in JS land, you can follow SitePoint’s JavaScript channel on Twitter.
Please PM us if you have anything of interest for the next issue or if there is anything you would like to see featured. Paul and Chris of Arabia.

[Paul_Wilkins]

Thanks Chris. That tic-tac-toe one certainly needs some AI improvement. Anyone like seeing how they can improve on how it plays?

Recently I also came across Mancala, also known of as Kalah and Oware, where you have a 2x6 row of pots. It’s a sowing game, that looks simple but has some rather deep strategy elements to it.

[chrisofarabia]

I only played tic tac toe a few times, but it did feel a little basic - a fun throwaway for the newsletter though.

[Paul_Wilkins]

With the assignment operators piece, there is more to it than what appears on the surface. For example: with:

a = b = c;

Where they say:

…which will set the value of both a and b to 15. (You could read the expression as “a is equal to b which is equal to c”).

It doesn’t quite work in that way. Yes, a equals the result of b, but that assignment is delayed until after b has been assigned. The first one to be assigned is b which gets the value of c, but you have to be very careful because if b doesn’t yet exist, it will be made a global variable as window.b

Only after that is assigned the result of b.

So in effect, if you have the following code:

var a = b = c;

What is really happening instead is:

b = c;
var a = b;

And if that’s really how you want to assign your values, it’s best to write it as such to avoid confusion and bugs later on down the road.

I think that chaining assignments leads to problems when developers misunderstand what they’re looking at, and is best to be avoided in preference for clearer code that is less likely to be misunderstood.

[chrisofarabia]

In the back of my head, I think I knew that, but it’s definitely something that’s worth clarifying - especially for those quite new to JS (which includes me). I wonder how many people your example has caught out over the years?