其完成的代码为多个PDF Base64转换为一个单一的PDF文件

**https://cdn.jsdelivr.net/npm/pdf-lib@1.11.0/dist/pdf-lib.min.js**在html文件中添加脚本：

var base64PDFs = [
    "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"
    ,"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"
];

mergePDFs(base64PDFs);

async function mergePDFs(base64PDFs) {
    const mergedPDF = await PDFLib.PDFDocument.create();

    for (const base64PDF of base64PDFs) {
        const pdfBytes = Uint8Array.from(atob(base64PDF), c => c.charCodeAt(0));
        const pdfDoc = await PDFLib.PDFDocument.load(pdfBytes);
        const copiedPages = await mergedPDF.copyPages(pdfDoc, pdfDoc.getPageIndices());
        copiedPages.forEach(page => mergedPDF.addPage(page));
    }

    const mergedPDFBytes = await mergedPDF.save();
    const mergedPDFBase64 = btoa(String.fromCharCode.apply(null, mergedPDFBytes));
    // Use the mergedPDFBase64 as needed (e.g., download or display)
    console.log(mergedPDFBase64);
    makeMergePDF(mergedPDFBase64)
}

   
function makeMergePDF(base64Data) {
    var arrBuffer = base64ToArrayBuffer(base64Data);
    // It is necessary to create a new blob object with mime-type explicitly set
    // otherwise only Chrome works like it should
    var newBlob = new Blob([arrBuffer], { type: "application/pdf" });
    // IE doesn't allow using a blob object directly as link href
    // instead it is necessary to use msSaveOrOpenBlob
    if (window.navigator && window.navigator.msSaveOrOpenBlob) {
        window.navigator.msSaveOrOpenBlob(newBlob);
        return;
    }
    // For other browsers: 
    // Create a link pointing to the ObjectURL containing the blob.
    var data = window.URL.createObjectURL(newBlob);

    var link = document.createElement('a');
    document.body.appendChild(link); //required in FF, optional for Chrome
    link.href = data;
    link.download = "file.pdf";
    link.click();
    window.URL.revokeObjectURL(data);
    link.remove();
}
function base64ToArrayBuffer(data) {
    var binaryString = window.atob(data);
    var binaryLen = binaryString.length;
    var bytes = new Uint8Array(binaryLen);
    for (var i = 0; i < binaryLen; i++) {
        var ascii = binaryString.charCodeAt(i);
        bytes[i] = ascii;
    }
    return bytes;
};

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