Recently, TC39 decided on the final semantics of classes in ECMAScript 6 [^2]. This blog post explains how their final incarnation works. The most significant recent changes were related to how subclassing is handled.

This blog post examines how variables and scoping are handled in ECMAScript 6 [^1].

Update 2015-02-05: More information – “Experimental New Directions for JavaScript” by Andreas Rossberg (slides in English).

Google is currently working on SoundScript, a way to speed up object-oriented programming in JavaScript. The content of this blog post is completely based on a recent talk [^1] by Dmitry Lomov. That is, everything I have written here is inferred from those slides and may or may not be correct.

Note: This blog post describes first ideas, avenues that Google is exploring for making JavaScript OOP faster. The final version of SoundScript may look and work completely different.

You can now try out Flow [^1], Facebook’s typechecker for JavaScript, online, at tryflow.org.

The blog post covers new features of strings in ECMAScript 6 (ES6).

Aurelia is a new framework by Durandal creator Rob Eisenberg (which helps credibility-wise).

It uses an interesting combination of technologies/techniques:

• Web Components: as an infrastructure for widgets (polyfilled where necessary)
• 6to5: to compile ECMAScript 6 to ECMAScript 5
• jspm: for package management
• MVVM (as used by Knockout and the Knockout-inspired Durandal): as a UI pattern

ECMAScript 6 (ES6) supports destructuring, a convenient way to extract values from data stored in (possibly nested) objects and arrays. This blog post describes how it works and gives examples of its usefulness. Additionally, parameter handling receives a significant upgrade in ES6: it becomes similar to and supports destructuring, which is why it is explained here, too.