Crate boa_runtime

Boa’s boa_runtime crate contains an example runtime and basic runtime features and functionality for the boa_engine crate for runtime implementors.

Example: Adding Web API’s Console Object

1. Add boa_runtime as a dependency to your project along with boa_engine.

use boa_engine::{js_string, property::Attribute, Context, Source};
use boa_runtime::Console;

// Create the context.
let mut context = Context::default();

// Initialize the Console object.
let console = Console::init(&mut context);

// Register the console as a global property to the context.
context
    .register_global_property(js_string!(Console::NAME), console, Attribute::all())
    .expect("the console object shouldn't exist yet");

// JavaScript source for parsing.
let js_code = "console.log('Hello World from a JS code string!')";

// Parse the source code
match context.eval(Source::from_bytes(js_code)) {
    Ok(res) => {
        println!(
            "{}",
            res.to_string(&mut context).unwrap().to_std_string_escaped()
        );
    }
    Err(e) => {
        // Pretty print the error
        eprintln!("Uncaught {e}");
    }
};

About Boa

Boa is an open-source, experimental ECMAScript Engine written in Rust for lexing, parsing and executing ECMAScript/JavaScript. Currently, Boa supports some of the language. More information can be viewed at Boa’s website.

Try out the most recent release with Boa’s live demo playground.

Boa Crates

• boa_cli - Boa’s CLI && REPL implementation
• boa_ast - Boa’s ECMAScript Abstract Syntax Tree.
• boa_engine - Boa’s implementation of ECMAScript builtin objects and execution.
• boa_gc - Boa’s garbage collector.
• boa_icu_provider - Boa’s ICU4X data provider.
• boa_interner - Boa’s string interner.
• boa_macros - Boa’s macros.
• boa_parser - Boa’s lexer and parser.
• boa_profiler - Boa’s code profiler.
• boa_runtime - Boa’s WebAPI features.
• boa_string - Boa’s ECMAScript string implementation.

Modules

url

Boa’s implementation of JavaScript’s URL Web API class.

Structs

Console

This is the internal console object state.

ConsoleState

The current state of the console, passed to the logger backend. This should not be copied or cloned. References are only valid for the current logging call.

RegisterOptions

Options used when registering all built-in objects and functions of the WebAPI runtime.

TextDecoder

The TextDecodermdn class represents an encoder for a specific method, that is a specific character encoding, like utf-8.

TextEncoder

The TextEncodermdn class represents an encoder for a specific method, that is a specific character encoding, like utf-8.

Traits

Logger

A trait that can be used to forward console logs to an implementation.

Functions

register

Register all the built-in objects and functions of the WebAPI runtime.