PrimJS is a lightweight, high-performance JavaScript engine designed specifically for the Lynx cross-platform framework. Fully supporting ES2019, PrimJS is built on top of QuickJS and delivers superior performance and a better development experience compared to QuickJS.

Key features include:

• Optimized Interpreter: PrimJS introduces a template interpreter leveraging stack caching and register optimizations, significantly enhancing performance.
• Seamless Object Model Integration: The engine's object model integrates efficiently with the Lynx object model, reducing data communication overhead and improving rendering performance.
• Advanced Memory Management: Utilizing a Garbage Collector (GC) instead of QuickJS's Reference Counting, PrimJS offers better performance, improved memory analyzability, and reduced risk of memory leaks.
• Comprehensive Debugging Support: Full implementation of the Chrome DevTools Protocol (CDP) enables seamless integration with Chrome Debugger for enhanced debugging capabilities.

Performance

For detailed performance benchmarks, please refer to performance comparison document. The benchmark results show that PrimJS outperforms QuickJS by approximately 28% in overall score (3735 vs 2904) on the Octane Benchmark suite. We are continuously working on performance optimizations.

Quick Start

Dependencies

1. Clone the repository:

   git clone [email protected]:lynx-family/primjs.git

2. Install dependencies:

   cd primjs
   source tools/envsetup.sh
   hab sync .

Building on Linux and macOS

PrimJS uses gn and ninja for building. Follow these steps to generate the qjs binary:

gn gen out/Default
ninja -C out/Default qjs_exe

To enable the template interpreter and garbage collector, use the following gn arguments (for example, on the arm64 platform, these arguments configure the build system to target ARM64 architecture while enabling the bytecode-based template interpreter and automatic memory management):

gn gen out/Default --args= '
    target_cpu="arm64" 
    enable_primjs_snapshot = true
    enable_compatible_mm = true
    enable_tracing_gc = true'
ninja -C out/Default -j32 qjs_exe

Release Build

For a release build, set the is_debug = false argument during configuration.

Running PrimJS

The primary binary is qjs, located at out/Default/qjs. Use it to run JavaScript files:

./out/Default/qjs test.js

Running Tests

Run the following steps from the root directory to build and execute unit tests:

Build Unit Tests

python3 tools/ci/check_test_build.py

Run Unit Tests

python3 tools/ci/check_test_run.py

How to Contribute

Code of Conduct

We are devoted to ensuring a positive, inclusive, and safe environment for all contributors. Please find our Code of Conduct for detailed information.

Contributing Guide

We welcome you to join and become a member of Lynx Authors. It's people like you that make this project great.

Please refer to lynx contributing guide for details.

Open Source Roadmap

Discussions

Large discussions and proposals are discussed in Github Discussions

License

PrimJS is Apache licensed, as found in the LICENSE file.