By: +David Herron; Date: 2014-03-15 22:03
The only problem with that is, the book was published in mid-2012, and it's now early 2014, and surely the ECMAScript committee has moved the Harmony project forward a bit. For the up-to-date list of what the committee is doing, see their Wiki at: http://wiki.ecmascript.org/doku.php?id=harmony:harmony
The bulk of the book talks about ECMAScript.next. According to the book, ECMAScript.next was to have finished by the end of 2013, but I see from their Wiki that didn't happen, and that there's several features still in the Strawman queue.