V8 and other modern JavaScript engines get their speed via just-in-time (JIT) compilation of script to native machine code immediately prior to execution. Code is initially compiled by a baseline compiler, which can generate non-optimized machine code quickly. The compiled code is analyzed during runtime and optionally re-compiled dynamically with a more advanced optimizing compiler for peak performance. In V8, this script execution pipeline has a variety of special cases and conditions which require complex machinery to switch between the baseline compiler and two optimizing compilers, Crankshaft and TurboFan.

BlinkOn is a biannual meeting of Blink, V8, and Chromium contributors. BlinkOn 6 was held in Munich on June 16 and June 17. The V8 team gave a number of presentations on architecture, design, performance initiatives, and language implementation.

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 5.3, which will be in beta until it is released in coordination with Chrome 53 Stable. V8 v5.3 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.

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.

The V8 team places great importance on the evolution of JavaScript into an increasingly expressive and well-defined language that makes writing fast, safe, and correct web applications easy. In June 2015, the ES2015 specification was ratified by the TC39 standards committee, making it the largest single update to the JavaScript language. New features include classes, arrow functions, promises, iterators / generators, proxies, well-known symbols, and additional syntactic sugar. TC39 has also increased the cadence of new specifications and released the candidate draft for ES2016 in February 2016, to be ratified this summer. While not as expansive as the ES2015 update due to the shorter release cycle, ES2016 notably introduces the exponentiation operator and Array.prototype.includes.

The first step in the V8 release process is a new branch from the Git master immediately before Chromium branches for a Chrome Beta milestone (roughly every six weeks). Our newest release branch is V8 v5.1, which will remain in beta until we release a stable build in conjunction with Chrome 51 Stable. Here’s a highlight of the new developer-facing features in this version of V8.

In a previous blog post, we introduced the problem of jank caused by garbage collection interrupting a smooth browsing experience. In this blog post we introduce three optimizations that lay the groundwork for a new garbage collector in V8, codenamed Orinoco. Orinoco is based on the idea that implementing a mostly parallel and concurrent garbage collector without strict generational boundaries will reduce garbage collection jank and memory consumption while providing high throughput. Instead of implementing Orinoco behind a flag as a separate garbage collector, we decided to ship features of Orinoco incrementally on V8 tip of tree to benefit users immediately. The three features discussed in this post are parallel compaction, parallel remembered set processing, and black allocation.

The first step in the V8 release process is a new branch from the Git master immediately before Chromium branches for a Chrome Beta milestone (roughly every six weeks). Our newest release branch is V8 v5.0, which will remain in beta until we release a stable build in conjunction with Chrome 50 Stable. Here’s a highlight of the new developer-facing features in this version of V8.

For a comprehensive overview of WebAssembly and a roadmap for future community collaboration, see A WebAssembly Milestone on the Mozilla Hacks blog.

Since June 2015, collaborators from Google, Mozilla, Microsoft, Apple and the W3C WebAssembly Community Group have been hard at work designing, specifying, and implementing (1, 2, 3, 4) WebAssembly, a new runtime and compilation target for the web. WebAssembly is a low-level, portable bytecode that is designed to be encoded in a compact binary format and executed at near-native speed in a memory-safe sandbox. As an evolution of existing technologies, WebAssembly is tightly integrated with the web platform, as well as faster to download over the network and faster to instantiate than asm.js, a low-level subset of JavaScript.

Introduced with the third edition of the ECMA-262 specification, regular expressions have been part of Javascript since 1999. In functionality and expressiveness, JavaScript’s implementation of regular expressions roughly mirrors that of other programming languages.