Self-hosted code is JavaScript code that SpiderMonkey uses to implement some of its intrinsic functions for JavaScript. Because it is written in JavaScript, it gets all the benefits of our JITs, like inlining and inline caches.

The Temporal proposal provides a replacement for Date, a long standing pain-point in the JavaScript language. This blog post describes some of the history and motivation behind the proposal. The Temporal API itself is well docmented on MDN.

Hello everyone,

In October 2024, I joined Outreachy as an Open Source contributor and in December 2024, I joined Outreachy as an intern working with Mozilla. My role was to implement the TC39 Range Proposal in the SpiderMonkey JavaScript engine. Iterator.range is a new built-in method proposed for JavaScript iterators that allows generating a sequence of numbers within a specified range. It functions similarly to Python’s range, providing an easy and efficient way to iterate over a series of values:

Recently I got to land a patch which touches a cool optimization, that I had to really make sure I understood deeply. As a result, I wrote a huge commit message. I’d like to expand that message a touch here and turn it into a nice blog post.

After many long years, the Memory64 proposal for WebAssembly has finally been released in both Firefox 134 and Chrome 133. In short, this proposal adds 64-bit pointers to WebAssembly.

Hello! Welcome to another episode of the SpiderMonkey Newsletter. I’m your host, Matthew Gaudet.

In September, machine learning engineers at Mozilla filed a bug report indicating that Firefox was consuming excessive memory and CPU resources while running Microsoft’s ONNX Runtime (a machine learning library) compiled to WebAssembly.

Hello everyone!

Hello Everyone,