如何解决此错误“ TypeError：无法读取未定义的属性'GetQuote'”？

Question

我试图通过回送项目中的SOAP服务将JSON转换为XML。 我使用了strong-soap npm库。 但是我找不到将JSON转换为XML的解决方案。

我尝试过。

var soap = require('strong-soap').soap;
    var XMLHandler = soap.XMLHandler;
    var xmlHandler = new XMLHandler();
    var util = require('util');
    var url = 'http://www.webservicex.net/stockquote.asmx?WSDL';

    var requestArgs = {
      symbol: 'IBM'
    };

    var options = {};
    var clientOptions = {};
    soap.createClient(url, clientOptions, function(err:any, client:any) {
      var customRequestHeader = {customheader1: 'test1'};
      client.GetQuote(requestArgs, function(err:any, result:any, envelope:any, soapHeader:any) {
        // Convert 'result' JSON object to XML
        var node = xmlHandler.jsonToXml(null, null,
          XMLHandler.createSOAPEnvelopeDescriptor('soap'), result);
        var xml = node.end({pretty: true});
        console.log(xml);

        // Convert XML to JSON object
        var root = xmlHandler.xmlToJson(null, xml, null);
        console.log('%s', util.inspect(root, {depth: null}));

      }, options, customRequestHeader);
    });

错误。

TypeError: Cannot read property 'GetQuote' of undefined
    at /.../dist/controllers/payments.controller.js:165:20
    at /.../node_modules/strong-soap/src/soap.js:54:5
    at /home/milutin/Sources/boom-platform-api/api/node_modules/strong-soap/src/soap.js:36:16
    at /.../node_modules/strong-soap/src/parser/wsdl.js:487:13
    at Request._callback (/.../node_modules/strong-soap/src/http.js:169:9)
    at Request.self.callback (/.../node_modules/request/request.js:185:22)
    at Request.emit (events.js:198:13)
    at Request.<anonymous> (/.../node_modules/request/request.js:1161:10)
    at Request.emit (events.js:198:13)
    at IncomingMessage.<anonymous> (/.../node_modules/request/request.js:1083:12)
    at Object.onceWrapper (events.js:286:20)
    at IncomingMessage.emit (events.js:203:15)
    at endReadableNT (_stream_readable.js:1129:12)
    at process._tickCallback (internal/process/next_tick.js:63:19)

如何解决此错误？ 谢谢。