Boa

This is an experimental Javascript lexer, parser and Just-in-Time compiler written in Rust. Currently, it has support for some of the language.

This project is an attempted rewrite of Bebbington's js.rs. Most of the Rust code has been rewritten from scratch.

Live Demo

https://jasonwilliams.github.io/boa/

You can get more verbose errors when running from the commnand line

Contributing

If you don't already have Rust installed rustup is the recommended tool to use. It will install Rust and allow you to switch between nightly, stable and beta. You can also install additional components.

curl https://sh.rustup.rs -sSf | sh

Then simply clone this project and cargo build To develop on the web assembly side you can run yarn serve then go to http://localhost:8080

Web Assembly

This interpreter can be exposed to javascript! You can build the example locally with:

$ yarn install
$ yarn serve

In the console you can use window.evaluate to pass JavaScript in

Roadmap

• ~string.length~ - works in 0.1.5
• Better lexing of numbers
• Adding support for constructors - half working, in progress
• ~better environment and scope support~ - Finished (05/05/2019)
• ~let and const support~
• Better error output
• Passing test262

Usage

• Checkout this project
• Build cargo build
• cargo run
• You can make changes to tests/js/test.js and build again
• If any JS doesn't work its a bug! Please raise an issue

Example