bit-core-file-type-finder

A lightweight and fast utility to detect file types based on magic bytes (file signatures) — similar to magic-bytes, built in TypeScript.

🔍 Features

• Detect file types by inspecting the first few bytes (magic numbers).
• Zero dependencies.
• Supports common formats like PNG, JPG, GIF, PDF, and more.
• Easily extendable with your own magic byte signatures.

📦 Installation

npm install bit-core-file-type-finder

🚀 Usage

import * as fs from 'fs';
import { detectFileType } from 'bit-core-file-type-finder';

const fileBuffer = fs.readFileSync('example.jpg');
const result = detectFileType(fileBuffer);

console.log(result);
// { ext: 'jpg', mime: 'image/jpeg', signature: [255, 216, 255] }

🧩 API

detectFileType(buffer: Uint8Array): MagicByteSignature | null
Scans the given buffer and returns matching file type information if found.

MagicByteSignature
ts
Copy
Edit
interface MagicByteSignature {
  ext: string;
  mime: string;
  signature: number[];
  offset?: number;
}

📄 LICENSE

This is a standard MIT License:

MIT License

Copyright (c) 2025 Jigar Joshi

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.