merge-pdfs.js

// Name: Merge pdfs
// Author: Lucas Sierota
// Description: Merge multiple pdfs into one
// Dependencies: pdf-lib

import "@johnlindquist/kit";

import fs from "fs/promises";
const { PDFDocument } = await npm("pdf-lib");

let name = await selectFile("Select a PDF file to merge");
const paths = [name];

// keep adding paths until there's no input
while (
  (await arg({
    placeholder: "Select another?",
    hint: `Press only y or n? [y]/[n]`,
  })) === "y"
) {
  name = await selectFile("Select another PDF file to merge");
  if (name !== "") paths.push(name);
}

// merge the pdfs
const pdfsToMerge = await Promise.all(
  paths.map(async (path) => await fs.readFile(path))
);
let finalPath = await selectFolder("Select a folder to save the merged PDF");
let finalName = await arg("Enter a name for the merged PDF");
finalPath = `${finalPath}${finalName}.pdf`;

try {
  const mergedPdf = await PDFDocument.create();
  for (const pdfBytes of pdfsToMerge) {
    const pdf = await PDFDocument.load(pdfBytes);
    const copiedPages = await mergedPdf.copyPages(pdf, pdf.getPageIndices());
    copiedPages.forEach((page) => {
      mergedPdf.addPage(page);
    });
  }

  const buf = await mergedPdf.save(); // Uint8Array
  let exists = await pathExists(finalPath);
  if (!exists) {
    await writeFile(finalPath, buf);
  } else {
    await div(md(`The path ${finalPath} already exists`));
  }
} catch (e) {
  log(`Error: ${e}`);
  await div(md(`Error: ${e}`));
}

await div(md(`Merged PDF saved to ${finalPath}`));