About This Book
It took a long time to finish it, but ECMAScript 6, the next version of JavaScript, is finally a reality:
It became a standard on 17 June 2015.
Most of its features are already widely available (as documented in kangax’ ES6 compatibility table).
Transpilers (such as Babel) let you compile ES6 to ES5.
The next sections explain concepts that are important in the world of ES6.