Mathias Bynens

About me

Hi there! I’m Mathias. I work on the V8 JavaScript engine at Google. HTML, CSS, JavaScript, Unicode, performance, and security get me excited. You can follow me on Twitter and GitHub.

Latest notes

JavaScript engine fundamentals: Shapes and Inline Caches

· tagged with JavaScript, performance

This article describes some key fundamentals that are common to all JavaScript engines — and not just V8, the engine the authors work on. As a JavaScript developer, having a deeper understanding of how JavaScript engines work helps you reason about the performance characteristics of your code.

Continue reading “JavaScript engine fundamentals: Shapes and Inline Caches”…

Asynchronous stack traces: why await beats .then()

· tagged with JavaScript, performance

Compared to using promises directly, not only can async and await make code more readable for developers — they enable some interesting optimizations in JavaScript engines, too! This write-up is about one such optimization involving stack traces for asynchronous code.

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ECMAScript regular expressions are getting better!

· tagged with JavaScript, Unicode

This article highlights what’s happening in the world of JavaScript regular expressions right now. Spoiler: it’s quite a lot — there are more RegExp-related proposals currently advancing through the TC39 standardization process than there have been updates to RegExp in the history of ECMAScript!

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Unicode property escapes in JavaScript regular expressions

· tagged with JavaScript, Unicode

ES2018 adds support for Unicode property escapes of the form \p{…} and \P{…} to JavaScript regular expressions. This article explains what Unicode property escapes are, how they work, and why they’re useful.

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ES2015 const is not about immutability

· tagged with JavaScript

This seems to be a very common misconception that just won’t die. I keep running into it in blog posts, Twitter discussions, and even books.

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