使用reactjs将多个Base64解码的pdf合并为一个pdf

import React, { useState } from 'react';
import { PDFDocument } from 'pdf-lib';

const PDFMergeComponent = () => {
  const [pdfFiles, setPdfFiles] = useState([]);

  const decodeBase64PDF = async (base64) => {
    const pdfBytes = atob(base64);
    const pdfDoc = await PDFDocument.load(pdfBytes);
    return pdfDoc;
  };

  const mergePDFs = async () => {
    const mergedPDF = await PDFDocument.create();

    for (const pdf of pdfFiles) {
      const decodedPDF = await decodeBase64PDF(pdf);
      const pages = await mergedPDF.copyPages(decodedPDF, decodedPDF.getPageIndices());
      pages.forEach((page) => mergedPDF.addPage(page));
    }

    const mergedPDFBytes = await mergedPDF.save();
    const mergedPDFBase64 = btoa(mergedPDFBytes);

    const downloadLink = document.createElement('a');
    downloadLink.href = `data:application/pdf;base64,${mergedPDFBase64}`;
    downloadLink.download = 'merged.pdf';
    downloadLink.click();
  };

  const handleFileChange = (event) => {
    const selectedFiles = Array.from(event.target.files);
    const base64Promises = selectedFiles.map((file) => {
      return new Promise((resolve, reject) => {
        const reader = new FileReader();
        reader.onload = (event) => resolve(event.target.result);
        reader.onerror = (error) => reject(error);
        reader.readAsDataURL(file);
      });
    });

    Promise.all(base64Promises)
      .then((base64Files) => {
        setPdfFiles(base64Files);
      })
      .catch((error) => {
        console.error('Error decoding PDF files:', error);
      });
  };

  return (
    <div>
      <input type="file" multiple onChange={handleFileChange} />
      <button onClick={mergePDFs}>Merge PDFs</button>
    </div>
  );
};

export default PDFMergeComponent;