README.md

filefs (Node.js)

Pure JavaScript ESM port of FileFS for Node.js 18+.

The Node port uses the same on-disk format as the C, Go, Java, .NET, Rust, and Zig ports:

• 512-byte blocks
• magic number 78 11 45 14
• copy-on-write journal stored beside the image as <image>-j

Install / use locally

cd nodejs
npm test

API

import { FileSystem, SeekWhence, FileType } from "filefs";

FileSystem.mkfs("demo.ffs");

const fsys = new FileSystem();
fsys.mount("demo.ffs");

fsys.mkdir("docs");
fsys.chdir("docs");

const file = fsys.open("note.txt", "w");
fsys.write(file, Buffer.from("hello"));
fsys.close(file);

const reader = fsys.open("note.txt", "r");
const buffer = Buffer.alloc(16);
const read = fsys.read(reader, buffer);
fsys.close(reader);

console.log(buffer.subarray(0, read).toString("utf8"));
console.log(fsys.getcwd()); // /docs/

Exports

• FileSystem
• FileHandle
• DirectoryHandle
• SeekWhence
• FileType
• FileFsError

Notes

• File I/O is synchronous to keep the implementation close to the reference ports.
• Paths follow FileFS semantics, including trailing / in getcwd() for non-root directories.
• Directory iteration returns { name, nameLength, type }.