From November 27-29, 2012, the Ecma Technical Committee 39 (TC39, [1]) had another meeting, where decisions were made about ECMAScript.next (the code name for ECMAScript 6 [1]). This blog post summarizes and explains the highlights. It is based on Rick Waldrons excellent notes that he put up on GitHub. There is also a list of all 2ality posts on TC39 meetings.

Update 2014-08-04: Comprehensions won’t be in ECMAScript 6. There’s a chance that an updated version of them will be in ECMAScript 7 or later.

ECMAScript.next will have two kinds of comprehensions: array comprehensions and generator comprehensions. They allow one to quickly assemble an array or a sequence of elements. Comprehensions exist in many programming languages, for example: CoffeeScript, Python, Haskell, Clojure.

In languages whose syntax is derived from C (e.g.: C ← C++ ← Java ← JavaScript), two brace styles are most common: Allman style and 1TBS.

In JavaScript, there is an unfortunate overloading of the term “prototype”.

2012 has been a very productive JavaScript year for me:

I’m a big fan of blogs. After all, I’m writing one, myself. They are the contemporary version of a specialized newspaper. Regularly having new content is exciting and reading blogs is well supported by various apps, thanks to standardized publication formats such as RSS and Atom.

Update 2012-12-27: Better example for aliasing in Sect. 1.

In a blog post, David Walsh mentions two approaches for emptying (clearing) an array. This blog post explains the pros and cons of both approaches. In order to understand them, we first need to know about aliasing.

ECMAScript 6 [1] will bring many new features to the language. However, it will be years before we can rely on it being supported in most browsers that are in use. This post examines tools that will allow us to program with ECMAScript 6 much sooner.

The following puzzle has been posted on Reddit by davvblack: What are the values of x and y, given the following interaction?

    > x === y
    true
    > 1/x > 1/y
    true