base on Boa is an embeddable Javascript engine written in Rust. # Boa <p align="center"> <a href="https://boajs.dev/"> <picture> <source media="(prefers-color-scheme: dark)" srcset="./assets/logo_yellow.svg"> <source media="(prefers-color-scheme: light)" srcset="./assets/logo_black.svg"> <img alt="Boa logo" src="./assets/logo.png"> </picture> </a> </p> Boa is an experimental JavaScript lexer, parser and interpreter written in Rust 🦀, it has support for **more** than 90% of the latest ECMAScript specification. We continuously improve the conformance to keep up with the ever-evolving standard. [![Build Status][build_badge]][build_link] [](https://codecov.io/gh/boa-dev/boa) [](https://crates.io/crates/boa_engine) [](https://docs.rs/boa_engine) [](https://discord.gg/tUFFk9Y) [](https://matrix.to/#/#boa:matrix.org) [build_badge]: https://github.com/boa-dev/boa/actions/workflows/rust.yml/badge.svg?event=push&branch=main [build_link]: https://github.com/boa-dev/boa/actions/workflows/rust.yml?query=event%3Apush+branch%3Amain ## ⚡️ Live Demo (WASM) Try out the engine now at the live WASM playground [here](https://boajs.dev/playground)! Prefer a CLI? Feel free to try out `boa_cli`! ## 📦 Crates Boa currently publishes and actively maintains the following crates: - **`boa_ast`** - Boa's ECMAScript Abstract Syntax Tree - **`boa_cli`** - Boa's CLI && REPL implementation - **`boa_engine`** - Boa's implementation of ECMAScript builtin objects and execution - **`boa_gc`** - Boa's garbage collector - **`boa_interner`** - Boa's string interner - **`boa_parser`** - Boa's lexer and parser - **`boa_icu_provider`** - Boa's ICU4X data provider - **`boa_runtime`** - Boa's WebAPI features - **`boa_string`** - Boa's ECMAScript string implementation. - **`tag_ptr`** - Utility library that enables a pointer to be associated with a tag of type `usize`. > [!NOTE] > > The `Boa` and `boa_unicode` crates are deprecated. ## 🚀 Example To start using Boa simply add the `boa_engine` crate to your `Cargo.toml`: ```toml [dependencies] boa_engine = "0.20.0" ``` Then in `main.rs`, copy the below: ```rust use boa_engine::{Context, Source, JsResult}; fn main() -> JsResult<()> { let js_code = r#" let two = 1 + 1; let definitely_not_four = two + "2"; definitely_not_four "#; // Instantiate the execution context let mut context = Context::default(); // Parse the source code let result = context.eval(Source::from_bytes(js_code))?; println!("{}", result.display()); Ok(()) } ``` Now, all that's left to do is `cargo run`. Congrats! You've executed your first JavaScript code using Boa! ## 🔎 Documentation For more information on Boa's API, feel free to check out our documentation. [**API Documentation**](https://docs.rs/boa_engine/latest/boa_engine/) ## 🏅 Conformance To know more details about Boa's conformance surrounding the _ECMAScript_ specification, you can check out our _ECMASCript Test262_ test suite results [here](https://boajs.dev/conformance). ## 🪚 Contributing Please, check the [CONTRIBUTING.md](CONTRIBUTING.md) file to know how to contribute in the project. You will need Rust installed and an editor. We have some configurations ready for VSCode. ### 🐛 Debugging Check [debugging.md](./docs/debugging.md) for more info on debugging. ### 🕸 Web Assembly > [!IMPORTANT] > > This only applies to `wasm32-unknown-unknown` target, > `WASI` and `Emscripten` target variants are handled automatically. - Enable the `js` feature flag. - Set `RUSTFLAGS='--cfg getrandom_backend="wasm_js"'` The `rustflags` can also be set by adding a `.cargo/config.toml` file in the project root directory: ```toml [target.wasm32-unknown-unknown] rustflags = '--cfg getrandom_backend="wasm_js"' ``` For more information see: [`getrandom` WebAssembly Support][getrandom-webassembly-support] [getrandom-webassembly-support]: https://docs.rs/getrandom/latest/getrandom/index.html#webassembly-support ## ⚙️ Usage - Clone this repo. - Run with `cargo run -- test.js` in the project root directory where `test.js` is a path to an existing JS file with any valid JS code. - If any JS doesn't work then it's a bug. Please raise an [issue](https://github.com/boa-dev/boa/issues/)! ### Example  ### Command-line Options ```txt Usage: boa [OPTIONS] [FILE]... Arguments: [FILE]... The JavaScript file(s) to be evaluated Options: --strict Run in strict mode -a, --dump-ast [<FORMAT>] Dump the AST to stdout with the given format [possible values: debug, json, json-pretty] -t, --trace Dump the AST to stdout with the given format --vi Use vi mode in the REPL -O, --optimize --optimizer-statistics --flowgraph [<FORMAT>] Generate instruction flowgraph. Default is Graphviz [possible values: graphviz, mermaid] --flowgraph-direction <FORMAT> Specifies the direction of the flowgraph. Default is top-top-bottom [possible values: top-to-bottom, bottom-to-top, left-to-right, right-to-left] --debug-object Inject debugging object `$boa` -m, --module Treats the input files as modules -r, --root <ROOT> Root path from where the module resolver will try to load the modules [default: .] -h, --help Print help (see more with '--help') -V, --version Print version ``` ## 🧭 Roadmap See [Milestones](https://github.com/boa-dev/boa/milestones). ## 📊 Benchmarks The current benchmarks are taken from v8's benchmark that you can find [here][boa-benchmarks]. You can also view the results of nightly benchmark runs comparing Boa with other JavaScript engines [here](https://boajs.dev/benchmarks). If you wish to run the benchmarks locally, then run Boa in release using the `combined.js` script which contains all the sub-benchmarks in the `bench-v8` directory. ```bash cargo run --release -p boa_cli -- bench-v8/combined.js ``` > [!TIP] > > If you'd like to run only a subset of the benchmarks, you can modify the `Makefile` located in the [`bench-v8` directory][boa-benchmarks]. > Comment out the benchmarks you don't want to include, then run `make`. After that, you can run Boa using the same command as above. [boa-benchmarks]: https://github.com/boa-dev/data/tree/benchmarks/bench ## 🧠 Profiling See [Profiling](./docs/profiling.md). ## 📆 Changelog See [CHANGELOG.md](./CHANGELOG.md). ## 💬 Communication Feel free to contact us on [Matrix](https://matrix.to/#/#boa:matrix.org) if you have any questions. Contributor discussions take place on the same Matrix Space if you're interested in contributing. We also have a [Discord](https://discord.gg/tUFFk9Y) for any questions or issues. ## ⚖️ License This project is licensed under the [Unlicense](./LICENSE-UNLICENSE) or [MIT](./LICENSE-MIT) licenses, at your option. ", Assign "at most 3 tags" to the expected json: {"id":"14503","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"