how to digitally sign a PDF document with a certificat using Javascript?

Question

i was looking for a solution to digitally sign a pdf with a self-signed certificat and came across a video in youtube explaining the process using pdf-lib and node-signpdf libraries. However, after following the instructions it didnt work as intended and encountered a problem:

• i executed the command ( npm i ) and (npm start ) as shown in the github repo of the project.

repo : https://github.com/RichardBray/pdf_sign

Demo ( 8 mins video ) : https://www.youtube.com/watch?v=OFZK5lc70OI&list=PLXUfmx2SIgyICZP-rA84Sle_ghq30W89N&index=4&t=1s

import SignPDF from "./SignPDF";
import fs from "node:fs";
import path from "node:path";

async function main() {
  const pdfBuffer = new SignPDF(
    path.resolve("test_assets/minions.pdf"),
    path.resolve("test_assets/certificate.p12")
  );

  const signedDocs = await pdfBuffer.signPDF();
  const randomNumber = Math.floor(Math.random() * 5000);
  const pdfName = `./exports/exported_file_${randomNumber}.pdf`;

  fs.writeFileSync(pdfName, signedDocs);
  console.log(`New Signed PDF created called: ${pdfName}`);
}

main();

> [email protected] start
> npm run build && node dist/index.js

> [email protected] build
> ./node_modules/.bin/babel ./src -d ./dist

'.' is not recognized as an internal command
or external, an executable program or a batch file.

• i tried to run the code using VScode debugger and it displayed the following error :

Uncaught SyntaxError c:\\Users\\ACER\\Documents\\GitHub\\pdf_sign\\src\\index.js:1
import SignPDF from "./SignPDF";
^^^^^^

SyntaxError: Cannot use import statement outside a module
at compileFunction (undefined:352:18)
at wrapSafe (undefined:1031:15)
at Module.\_compile (undefined:1065:27)
at Module.\_extensions..js (undefined:1153:10)
at Module.load (undefined:981:32)
at Module.\_load (undefined:822:12)
at executeUserEntryPoint (undefined:81:12)
at \<anonymous\> (undefined:17:47)

Answer 1

it appears that the problem is OS related. In fact , the code works fine under linux OS but have some issues with Windows OS related to import command. For windows OS replacing "import" commands with "require" commands solves the problem.

BEFORE:

import SignPDF from "./SignPDF";
import fs from "node:fs";
import path from "node:path";

AFTER :

const SignPDF =  require("./SignPDF");
const fs =  require("node:fs");
const path =  require("node:path");

Edit: Whenever imports are found in the project they should be replaced with require commands . https://jobs.czconsultants.com/utils/convert-imports-to-require-online/0 this website helps converting multiple commands fast