V8 is a popular embeddable JavaScript engine, perhaps most famously used to power the popular Node development framework or as the JavaScript engine used by Chrome. They just announced the release of version 5.2. From the release notes V8 gained the following features:
ES6 & ES7 support
V8 5.2 contains support for ECMAScript 6 (aka ES2015) and ECMAScript 7 (aka ES2016).
Exponentiation operator
This release contains support for the ES7 exponentiation operator, an infix notation to replace Math.pow.
let n = 3**3; // n == 27 n **= 2; // n == 729Evolving spec
For more information on the complexities behind support for evolving specifications and continued standards discussion around web compatibility bugs and tail calls, see the V8 blog post ES6, ES7, and beyond.
Performance
V8 5.2 contains further optimizations to improve the performance of JavaScript built-ins, including improvements for Array operations like the isArray method, the in operator, andFunction.prototype.bind. This is part of ongoing work to speed up built-ins based on new analysis of runtime call statistics on popular web pages. For more information, see the V8 Google I/O 2016 talk and look for an upcoming blog post on performance optimizations gleaned from real-world websites.
V8 API
Please check out our summary of API changes. This document gets regularly updated a few weeks after each major release.