= bundeno

Write once, run on Deno and Bun.

Overview

bundeno is a runtime compatibility layer that enables JavaScript/TypeScript code to run seamlessly on both Deno and Bun runtimes.

Instead of polyfilling missing APIs, bundeno detects your runtime and delegates to native implementations—giving you the best of both worlds.

Features

• Runtime Detection — Detect Deno, Bun, Node.js, or browser at runtime

• Unified File System — readTextFile, writeFile, readDir, stat, etc.

• Process Abstraction — Environment variables, subprocess execution, cwd

• Type-Safe — Full TypeScript support with proper types

• Zero Dependencies — No external packages required

• Future: Zig Native — Performance-critical FFI via shared Zig libraries

Quick Start

import { RUNTIME, isDeno, isBun } from "bundeno/runtime";
import { readTextFile, writeTextFile } from "bundeno/fs";
import { exec, getEnv } from "bundeno/process";

// Works on both Deno and Bun!
console.log(`Running on: ${RUNTIME}`);

const content = await readTextFile("./config.json");
const home = getEnv("HOME");
const result = await exec(["git", "status"]);

Installation

Deno

import { ... } from "jsr:@hyperpolymath/bundeno";

Bun

bun add @hyperpolymath/bundeno

API Reference

Runtime Detection

Function	Description
detectRuntime()	Returns "deno", "bun", "node", "browser", or "unknown"
isDeno()	Returns true if running on Deno
isBun()	Returns true if running on Bun
RUNTIME	Cached runtime value (evaluated once at import)

File System (bundeno/fs)

Function	Description
readTextFile(path)	Read file as UTF-8 string
readFile(path)	Read file as Uint8Array
writeTextFile(path, content)	Write string to file
writeFile(path, content)	Write bytes to file
exists(path)	Check if file/directory exists
stat(path)	Get file stats (size, mtime, isFile, etc.)
mkdir(path, options?)	Create directory (recursive by default)
remove(path, options?)	Remove file or directory
readDir(path)	List directory contents
copyFile(src, dest)	Copy a file
rename(src, dest)	Rename/move a file

Process (bundeno/process)

Function	Description
getEnv(key)	Get environment variable
setEnv(key, value)	Set environment variable
getAllEnv()	Get all environment variables
cwd()	Get current working directory
chdir(path)	Change current working directory
exit(code?)	Exit the process
args()	Get command line arguments
run(cmd, options?)	Run command and get result
exec(cmd, options?)	Run command and return stdout as string

Why bundeno?

The JavaScript runtime landscape is fragmented. Deno and Bun have different APIs for common operations:

Operation	Deno	Bun
Read file	Deno.readTextFile()	Bun.file().text()
Write file	Deno.writeTextFile()	Bun.write()
Subprocess	Deno.Command	Bun.spawn
FFI	Deno.dlopen	Native Zig imports

bundeno abstracts these differences so your code works everywhere.

Architecture

┌─────────────────────────────────────────────┐
│                Your Code                     │
└─────────────────────────────────────────────┘
                      │
                      ▼
┌─────────────────────────────────────────────┐
│              bundeno API                     │
│  (fs, process, sqlite, ffi, ...)            │
└─────────────────────────────────────────────┘
                      │
         ┌────────────┴────────────┐
         ▼                         ▼
┌─────────────────┐       ┌─────────────────┐
│   Deno Native   │       │   Bun Native    │
│   Deno.*        │       │   Bun.*         │
└─────────────────┘       └─────────────────┘

Roadmap

See ROADMAP.adoc for planned features.

• v0.1 — Foundation (fs, process, runtime detection)

• v0.2 — Extended APIs (SQLite, WebSocket, Crypto)

• v0.3 — Zig Native (shared FFI libraries)

• v1.0 — Stable API, full test coverage

Contributing

See CONTRIBUTING.adoc for guidelines.

License

PMPL-1.0-or-later. See LICENSE.txt.

Related Projects

• Deno — Secure runtime for JavaScript and TypeScript

• Bun — Fast all-in-one JavaScript runtime

• WinterCG — Web-interoperable Runtimes Community Group

• bunsenite — Nickel configuration parser (sibling project)