kevvais-pdf 
Check if a Buffer/Uint8Array is a PDF file
Install
$ npm install --save is-pdfUsage
var isPdf = require('is-pdf');
var read = require('fs').readFileSync;
isPdf(read('foo.pdf'));
// => trueCheck if a Buffer/Uint8Array is a 7ZIP file
Check if a Buffer/Uint8Array is a PDF file
$ npm install --save is-pdfvar isPdf = require('is-pdf');
var read = require('fs').readFileSync;
isPdf(read('foo.pdf'));
// => true