A JavaScript compiler and TypeScript checker written in Rust with a focus on static analysis and runtime performance.
Important
Ezno is in active development and currently does not support enough features to check existing projects. Check out the getting started guide for experimenting with what it currently supports.
What Ezno is
- A type checker for JavaScript usable through a CLI (with a LSP also in the works)
- A high level library that allows type checking to be added to other tools!
- Checks programs with guaranteed type safety (no runtime
TypeErrors) (as long as definitions are sound) - Types aimed at soundness and tracing for better static analysis
- A imperative type system that tracks and evaluates the side effects of functions and control flow structures. It is similar to an interpreter, but acts with types instead of values and does not run IO side effects etc
- A collection of experiments of types. Many are being worked out and are in the prototype stage. Some of the new behaviors benefit JavaScript specifically and others could be applied to other languages
- Fast
- Small
- Written in Rust
- Open source! You can help build Ezno!
- A challenge to the status quo of type checking, optimisations and compilation through deeper static analysis beyond syntax analysis
What Ezno is not
- eNZo, the Z is in front of the N (pronounce as 'Fresno' without the 'fr') 😀
- Be on parity with TSC or 1:1, it has some different behaviors but should work in existing projects using TSC (check out stc that is written in Rust and is aimed at replicating TSC)
- A binary executable compiler. It takes in JavaScript (or a TypeScript or Ezno superset) and does similar processes to traditional compilers, but at the end emits JavaScript. However in the future it could generate a lower level format using its event (side-effect) representation
Read more about Ezno
This project is a workspace consisting of a few crates:
| Crate | Lines Of Code | Contains |
|---|---|---|
| checker | Stores for types and contexts, type checking logic and optional synthesis over the parser AST | |
| parser | AST definitions, logic for parsing, AST to string and visiting |
Check out good first issues and comment on discussions! Feel free to ask questions on parts of the code of the checking implementation.
Read CONTRIBUTING.md for information about building and testing the projects.