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Development Guide

QuickJS-ng is an open-source JavaScript engine that welcomes contributions from the community. This guide will help you get started with contributing to the project.

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Getting Started

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Prerequisites

  • Git
  • CMake 3.x or higher
  • A C compiler (GCC, Clang, MSVC, or TCC)
  • Make (on Unix-like systems)

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Cloning the Repository

git clone https://github.com/quickjs-ng/quickjs.git
cd quickjs

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Building QuickJS-ng

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Quick Build

The simplest way to build QuickJS-ng is using the helper Makefile: 
make
This will build the qjs and qjsc executables and other test tools.

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Debug Build

For development, you’ll want to create a debug build without optimizations: 
make debug

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Manual CMake Build

If you prefer to use CMake directly (required on Windows): 
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
For a debug build: 
cmake -B build -DCMAKE_BUILD_TYPE=Debug
cmake --build build

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Contribution Workflow

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Fork and Clone
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Fork the repository on GitHub and clone your fork locally:
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git clone https://github.com/YOUR_USERNAME/quickjs.git
cd quickjs
git remote add upstream https://github.com/quickjs-ng/quickjs.git
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Create a Branch
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Create a new branch for your changes:
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git checkout -b my-feature-branch
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Make Your Changes
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Edit the code, add tests, and ensure your changes follow the project’s coding style.
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Build and Test
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Build the project and run the test suite:
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make
make test
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Commit Your Changes
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Write clear, descriptive commit messages:
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git add .
git commit -m "Add feature: description of your changes"
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Push and Create a Pull Request
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Push your branch to your fork:
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git push origin my-feature-branch
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Then create a pull request on GitHub from your branch to the main QuickJS-ng repository.

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Development Tools

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Code Generation

If you modify bytecode or built-in modules, regenerate the generated code: 
make codegen

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Syntax Checking

Verify that generated C code compiles correctly: 
make jscheck

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C++ Compatibility

Test that the codebase compiles as C++: 
make cxxtest

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Statistics

View engine statistics and memory usage: 
make stats

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Build Options

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Amalgamated Build

Create a single-file amalgamated build: 
make amalgam
This generates quickjs-amalgam.zip containing a single quickjs-amalgam.c file.

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Shared Libraries

Build shared libraries instead of static: 
make BUILD_SHARED_LIBS=ON

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Examples

Build with examples enabled: 
make QJS_BUILD_EXAMPLES=ON

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Sanitizers

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Address Sanitizer (ASan) and Undefined Behavior Sanitizer (UBSan)

cmake -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo -DQJS_ENABLE_ASAN=ON -DQJS_ENABLE_UBSAN=ON
cmake --build build

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Memory Sanitizer (MSan)

export CC=clang
cmake -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo -DQJS_ENABLE_MSAN=ON
cmake --build build

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CI/CD

QuickJS-ng uses GitHub Actions for continuous integration. The CI pipeline tests:
  • Multiple platforms: Linux, macOS, Windows, FreeBSD, OpenBSD
  • Multiple compilers: GCC, Clang, MSVC, TCC, MinGW
  • Multiple architectures: x86, x64, ARM64, RISC-V, s390x
  • Sanitizers: ASan, UBSan, MSan
  • Special builds: Emscripten, WASI, Android, iOS
  • Test262 compliance suite
All pull requests must pass CI checks before being merged.

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Coding Guidelines

  • Follow the existing code style and conventions
  • Write clear, self-documenting code with comments where necessary
  • Add tests for new features and bug fixes
  • Ensure all tests pass before submitting a pull request
  • Keep commits focused and atomic
  • Write descriptive commit messages

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Getting Help

If you need help or have questions:
  • Check the project documentation
  • Open an issue on GitHub for bugs or feature requests
  • Review existing issues and pull requests for similar topics

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Authors

QuickJS-ng is maintained by @bnoordhuis, @saghul, and many contributors. The original QuickJS engine was created by Fabrice Bellard and Charlie Gordon.

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