Detector plugin for file-type that identifies PDF (Portable Document Format) files and selected PDF-based subtypes.

This plugin goes beyond simple magic-number detection and can inspect the internal PDF structure to distinguish between generic PDF files and specific producer formats such as Adobe Illustrator (.ai).

This detector is designed for well-formed PDF files and established PDF-based subtypes. Support for corrupted or non-conforming PDFs is intentionally limited and only considered when a deviation is both common and widely accepted.

npm install @file-type/pdf

The following example shows how to add the PDF detector to file-type:

import { FileTypeParser } from 'file-type';
import { detectPdf } from '@file-type/pdf';

const parser = new FileTypeParser({
  customDetectors: [detectPdf],
});

const fileType = await parser.fromFile('example.pdf');
console.log(fileType);

When a PDF is identified as PDF/A (based on XMP metadata such as pdfaid:part), the detector returns a result that includes an additional flag:

  export interface PdfTypeResult extends FileTypeResult {
  archive?: boolean;
}

Example result for a PDF/A file:

{
  ext: 'pdf',
  mime: 'application/pdf',
  archive: true
}

This allows consumers to distinguish archival PDFs from regular PDFs without introducing non-standard extensions or MIME types.

• .ai / application/illustrator: Adobe Illustrator
• .pdf / application/pdf: Generic Portable Document Format files, including PDF/A (archival PDF)

This project is licensed under the MIT License. Feel free to use, modify, and distribute it as needed.