Node.js 使用xmlcrypto时出现NodeJS XPath解析错误

我在使用xml-crypto库签名xml时遇到问题. 下面是我的代码:

  const fs = require("fs");
  const xmlCrypto = require("xml-crypto");
  const xpath = require("xpath");
  const dom = require("xmldom").DOMParser;

  var xml = "<book><title>Harry Potter</title></book>";
  var xmlDocument = new dom().parseFromString(xml, "text/xml");

  var node = xpath.select("//title", xmlDocument)[0];

  console.log(node.localName + ": " + node.firstChild.data);
  console.log("Node: " + node.toString());

  const privateKey = fs.readFileSync(
    "./certifications/universal-pk.pem",
    "utf-8"
  );

  console.log("privateKey", privateKey);

  const reference = {
    uri: "",
    transforms: ["canonicalize", "c14n"],
    digest算法rithm: "http://www.w3.org/2001/04/xmlenc#sha256",
  };

  const sig = new xmlCrypto.SignedXml();
  sig.addReference(reference);
  sig.signingKey = privateKey;
  sig.computeSignature(node);

和控制台日志(log):

title: Harry Potter
Node: <title>Harry Potter</title>
privateKey -----BEGIN PRIVATE KEY-----
.......
-----END PRIVATE KEY-----

[xmldom error]  invalid doc source
@#[line:0,col:undefined]
\api\node_modules\xml-crypto\node_modules\xpath\xpath.js:1278
                    throw new Error("XPath parse error");
                          ^

Error: XPath parse error

我还try 了 https://www.npmjs.com/package/xml-crypto

但是，我也收到了同样的错误信息.