有没有办法将附件添加到在JavaScript或其他免费应用编程接口中创建的eml文件？

// 创建eml文件内容
var emlContent = "From: sender@example.com\n" +
                 "To: recipient@example.com\n" +
                 "Subject: Test Email\n" +
                 "Content-Type: multipart/mixed; boundary=boundary1\n" +
                 "\n" +
                 "--boundary1\n" +
                 "Content-Type: text/plain\n" +
                 "\n" +
                 "This is the email body.\n" +
                 "--boundary1\n" +
                 "Content-Type: application/octet-stream\n" +
                 "Content-Disposition: attachment; filename=\"attachment.txt\"\n" +
                 "Content-Transfer-Encoding: base64\n" +
                 "\n" +
                 "SGVsbG8gd29ybGQ=\n" +
                 "--boundary1--";

// 创建eml文件
var emlBlob = new Blob([emlContent], {type: "message/rfc822"});

// 创建下载链接
var downloadLink = document.createElement("a");
downloadLink.href = URL.createObjectURL(emlBlob);
downloadLink.download = "email.eml";

// 触发下载
downloadLink.click();