TezX LocalFS

LocalFS is a lightweight, runtime-compatible file storage library for Bun applications. It allows you to save, read, delete, and serve files locally with automatic duplicate renaming, MIME type validation, and optional filename sanitization.

Features

• Save browser File objects to disk.
• Optional automatic renaming for duplicate filenames (file_1.txt, file_2.txt).
• Allowed MIME types and maximum file size validation.
• Optional filename sanitization.
• Public URL generation for serving files via a router.
• Works seamlessly in Bun and Node.js environments.
• Easy integration with TezX Router.

Installation

# Using npm
npm install @tezx/localfs

# Using Bun
bun add @tezx/localfs

Usage

TypeScript Example

import LocalFS from "@tezx/localfs";

// Initialize storage
const fs = new LocalFS({
  basePath: "uploads",        // Where files will be stored
  publicUrl: "/uploads",      // URL to serve publicly
  sanitize: true,             // Sanitize filenames
  autoRenameOnConflict: true, // Automatically rename duplicates
  maxFileSize: 10 * 1024 * 1024, // Max file size: 10MB
  allowedTypes: ["image/*", "application/pdf"], // Allowed MIME types
});

// Saving a file
const file = new File(["Hello world"], "hello.txt", { type: "text/plain" });
const info = await fs.saveFile(file, { folder: "docs" });

console.log(info);
/*
{
  savedPath: "uploads/docs/hello.txt",
  filename: "hello.txt",
  publicUrl: "/uploads/docs/hello.txt"
}
*/

// Reading a file
const content = await fs.readFile("docs/hello.txt");
console.log(new TextDecoder().decode(content));

// Deleting a file
await fs.deleteFile("docs/hello.txt");

// Serve files publicly via TezX Router
import { Router } from "tezx";
const router = Router();
router.use(fs.serveFileResponse());

API

new LocalFS(options?: LocalFSOptions)

Creates a new LocalFS instance.

Options:

saveFile(file: File, option?: { filename?: string, folder?: string }) => Promise<SavedFileInfo>

Saves a file to disk.

Parameters:

• file: Browser/Fetch File object
• option.filename: Optional override for file name
• option.folder: Optional sub-folder under basePath

Returns: Promise<SavedFileInfo>

SavedFileInfo contains:

• savedPath: Absolute path on disk
• filename: Final filename used
• publicUrl: Public URL (if enabled)

readFile(filename: string) => Promise<ArrayBuffer>

Reads a file from disk.

• filename: Relative path under basePath or absolute path
• Returns: ArrayBuffer of file content

deleteFile(filename: string) => Promise<void>

Deletes a file from disk.

• filename: Relative path under basePath
• No-op if the file doesn't exist

serveFileResponse(config?: { onError?: (error: string, ctx: Context) => Response | Promise<Response> }) => Router

Returns a TezX Router instance that serves files publicly under publicUrl.

• config.onError: Optional error handler
• Throws error if allowPublicAccess is false