Lifo

A tiny Linux-like operating system, written in TypeScript, that runs anywhere JavaScript does -- a browser tab, a Node.js process, a serverless function. Not a VM, not an emulator -- a clean-room reimplementation of Unix in TypeScript, where the JS runtime is the kernel and its APIs are the system calls.

┌──────────────────────────────────────────────────┐
│                  Terminal UI                      │  xterm.js + Tokyo Night theme
├──────────────────────────────────────────────────┤
│                    Shell                          │  bash-like interpreter
├──────────────────────────────────────────────────┤
│            Command Registry / $PATH              │  ES module command map
├───────────┬────────────┬─────────────────────────┤
│ Coreutils │ Net Cmds   │ User Packages           │  each cmd = async function
├───────────┴────────────┴─────────────────────────┤
│          Node.js Compatibility Layer             │  thin wrappers over OS APIs
├──────────────────────────────────────────────────┤
│           Virtual Filesystem (VFS)               │  in-memory + IndexedDB persistence
├──────────────────────────────────────────────────┤
│              Kernel API Layer                    │  unified browser API wrappers
├──────────────────────────────────────────────────┤
│               Browser APIs                       │  fetch, streams, OPFS, etc.
└──────────────────────────────────────────────────┘

Getting Started

pnpm install
pnpm dev

Open http://localhost:5173 in a modern browser. You'll be greeted with a fully functional terminal.

pnpm build        # Production build
pnpm test         # Run test suite
pnpm typecheck    # Type check without emitting

What's Inside

Kernel

Virtual Filesystem (VFS) -- synchronous in-memory INode tree with full POSIX-like semantics (read, write, stat, mkdir, symlinks, hard links, permissions)
Virtual Providers -- /proc exposes system info (uptime, meminfo, cpuinfo, version) and /dev provides device files (null, zero, random, urandom)
Persistence -- IndexedDB-backed filesystem persistence with serialization/deserialization of the entire INode tree

Shell

A bash-like shell with:

Full lexer/parser/interpreter pipeline producing an AST
Pipes (ls | grep foo | wc -l), redirects (>, >>, <, 2>, &>)
Logical operators (&&, ||), sequences (;), background (&)
Variable expansion ($VAR, ${VAR:-default}), command substitution ($(...))
Glob expansion (*.txt, **/*.js), tilde expansion (~), brace expansion ({a,b,c})
Tab completion for commands, files, and directories
Command history with reverse search
Job control (Ctrl+C, fg, bg, jobs)
Builtins: cd, pwd, export, alias, source, read, test, echo, and more

60+ Commands

Category	Commands
Filesystem	`ls`, `cat`, `cp`, `mv`, `rm`, `mkdir`, `rmdir`, `touch`, `ln`, `stat`, `find`, `tree`, `du`, `df`, `chmod`, `file`, `basename`, `dirname`, `realpath`, `mktemp`
Text	`grep`, `sed`, `awk`, `head`, `tail`, `sort`, `uniq`, `wc`, `cut`, `tr`, `diff`, `nl`, `rev`
I/O	`printf`, `tee`, `xargs`, `yes`
Network	`curl`, `wget`, `ping`, `dig`
System	`ps`, `top`, `kill`, `env`, `uname`, `whoami`, `hostname`, `uptime`, `free`, `date`, `cal`, `bc`, `sleep`, `watch`, `which`, `man`, `help`
Archive	`tar`, `gzip`, `gunzip`, `zip`, `unzip`
Runtime	`node` (run JS with Node.js compat layer), `pkg` (package manager)

Node.js Compatibility Layer

Run JavaScript files with node script.js or node -e "code". The compatibility layer maps 15 Node.js standard library modules to browser APIs:

fs, path, events, buffer, util, os, process, http, child_process, stream, url, timers, crypto, console

Package Manager

pkg install <url>    # Install a package from URL
pkg remove <name>    # Uninstall a package
pkg list             # List installed packages
pkg info <name>      # Show package details

Filesystem Hierarchy

/
├── home/user/          # User home directory ($HOME)
├── tmp/                # Temporary files (in-memory)
├── etc/                # System configuration
├── var/log/            # System logs
├── usr/bin/            # Installed package binaries
├── proc/               # Virtual: system info (cpuinfo, meminfo, uptime)
├── dev/                # Virtual: devices (null, zero, random, urandom)
└── bin/                # Core commands

Tech Stack

TypeScript (strict mode, ESM throughout)
Vite for builds
xterm.js + WebGL addon for terminal rendering
Vitest for testing
Target: Chrome 110+, Firefox 110+, Safari 16.4+

Project Structure

src/
├── main.ts              # Boot sequence
├── kernel/              # VFS, persistence, virtual providers
├── shell/               # Lexer, parser, interpreter, expander, completer
├── commands/            # All 60+ commands organized by category
├── node-compat/         # Node.js standard library shims
├── pkg/                 # Package manager
├── terminal/            # xterm.js wrapper
└── utils/               # Path, args, glob, colors, encoding, archive
tests/                   # Mirrors src/ structure with full coverage

Related projects

Lifo is built by the team behind RapidNative — AI that generates production-ready React Native apps and UIs from a prompt — alongside these open-source tools:

Project	What it is
RapidNative	AI that generates production-ready React Native apps and UIs from a prompt
tinbase	A Supabase-compatible backend without Docker — one process, real Postgres, runs in the browser
ORCHD	A multi-tenant workload orchestrator — per-tenant workloads that sleep when idle and wake on the next request
jetplane	A Metro plugin and a thin dev server for Expo — many dev environments per machine

See them all on rapidnative.com/open-source.

License

MIT