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Work · November 9, 2024

Jaws – a JavaScript to WASM ahead-of-time compiler

I've open sourced a JavaScript to WASM compiler. It's an experimental tool, but given the semantics I already implemented, I'm fairly certain I am able to eventually cover 100% of JavaScript spec. Any ideas, questions or critique welcomed! If you are interested in WASM, especially with new proposals like WASM GC or exception handling, it might be a good source of seeing these features in action - the project has a few thousand lines of hand written WAT so far.

Jaws – a JavaScript to WASM ahead-of-time compiler launched on November 9, 2024 with 290 votes, #128 of 4,990 launches that month and more than 95% of that year's launches. The site was still online in September 2026, 1 year on.

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In plain words

Jaws is an open-source ahead-of-time compiler that converts JavaScript code into WebAssembly. Designed for developers interested in WebAssembly and its emerging features, the experimental tool demonstrates practical implementations of proposals like WASM garbage collection and exception handling through hand-written WebAssembly code. The project is in active development with the potential to eventually support the full JavaScript specification.

written from the facts on this page · September 2026

From the sources

JavaScript to WASM compiler. Contribute to drogus/jawsm development by creating an account on GitHub.

Jawsm (pronounced like "awesome") is a JavaScript to WebAssembly compiler written in Rust. It is similar to porffor in a way it also results in a standalone WASM binary that can be executed without an interpreter, but it takes a different implementation approach. It's an experimental tool and it's not ready for production. A lot of the language features and builtin types are missing or incomplete. That said, my goal is to eventually support 100% of the language. I started this project while working on a stress testing tool called Crows that runs WebAssembly scenarios. At the moment it only supports code compiled from Rust to WASM. As much as I love writing Rust, I also know it's not a…from github.com

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