JavaScript Runtime

Built on the V8 JavaScript engine, using a single-threaded event loop with non-blocking I/O for main execution, and supporting optional Worker threads for parallel tasks.

Supported operating systems

FullJS is designed to run exclusively on Linux-based systems.

• Debian 12 or newer
• Ubuntu (and other Debian-based derivatives)

A working systemd installation is required, as the runtime integrates with systemd for service management.

Supported architectures

• amd64
• arm64
• riscv64
• arm

Event System

• Uses epoll as the backend event notification facility for scalable, high-performance I/O.
• Optimized for large numbers of concurrent I/O operation.

Module System

• Supports only ES6 import/export syntax.
• Supports .js modules and native .so modules

Global Scope

Default global scope mimics a Web API-like environment but only relevant server-side features are exposed:

• Events (Event, EventTarget, CustomEvent)
• Timers (setTimeout, setInterval, etc.)
• Console (Console, console.log, console.error)
• Base64 utilities (atob, btoa)
• Encoding (TextEncoder, TextDecoder)
• Storage API (Storage, localStorage, sessionStorage)
• URL API (URL, URLSearchParams)
• Fetch API (fetch, Response, Request)
• Web Crypto API (crypto.getRandomValues, subtle.digest)
• Streams API (ReadableStream, WritableStream, TransformStream)
• Web Workers (Worker)
• Performance (performance.now)
• AbortController, AbortSignal
• DOMException

Directory Structure

FullJS follows the Linux Filesystem Hierarchy Standard (FHS) with specific locations for binaries, libraries, modules, and JavaScript files:

• /usr/bin/ – FullJS JavaScript binary (js), V8 snapshot (snapshot_blob.bin), and ICU data file (icudtl.dat)
• /usr/lib/fulljs/ – V8 shared libraries (e.g., libv8.so)
• /usr/lib/fulljs_modules/ – Native C++ modules (.so), such as fs, process, v4l2, etc.
• /usr/lib/fulljs_scope/ – JavaScript file defining the default global scope (globalscope.js)
• /usr/share/javascript/fulljs/ – Path for dynamically loadable JavaScript modules (e.g., path, Dialog, etc.)