V8 release v5.2

发布时间 · 标签: release

Roughly every six weeks, we create a new branch of V8 as part of our release process. Each version is branched from V8’s Git master immediately before Chrome branches for a Chrome Beta milestone. Today we’re pleased to announce our newest branch, V8 version 5.2, which will be in beta until it is released in coordination with Chrome 52 Stable. V8 5.2 is filled with all sorts of developer-facing goodies, so we’d like to give you a preview of some of the highlights in anticipation of the release in several weeks.

ES2015 & ES2016 support #

V8 v5.2 contains support for ES2015 (a.k.a. ES6) and ES2016 (a.k.a. ES7).

Exponentiation operator #

This release contains support for the ES2016 exponentiation operator, an infix notation to replace Math.pow.

let n = 3**3; // n == 27
n **= 2; // n == 729

Evolving 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 ES2015, ES2016, and beyond.

Performance #

V8 v5.2 contains further optimizations to improve the performance of JavaScript built-ins, including improvements for Array operations like the isArray method, the in operator, and Function.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.

Developers with an active V8 checkout can use git checkout -b 5.2 -t branch-heads/5.2 to experiment with the new features in V8 v5.2. Alternatively you can subscribe to Chrome's Beta channel and try the new features out yourself soon.