How to get value from XML string with Node.js

You can do it easier with camaro

const camaro = require('camaro')

const xml = `<yyy:response xmlns:xxx='http://example.com'> <yyy:success><yyy:data>some-value</yyy:data> </yyy:success></yyy:response>`

const template = {
    data: '//yyy:data'
}

console.log(camaro(xml, template))

Output:

{ data: 'some-value' }

node-xml2js library will help you.

var xml2js = require('xml2js');

var parser = new xml2js.Parser();
var xml = '\
<yyy:response xmlns:xxx="http://domain.com">\
    <yyy:success>\
        <yyy:data>some-value</yyy:data>\
    </yyy:success>\
</yyy:response>';
parser.parseString(xml, function (err, result) {
    console.dir(result['yyy:success']['yyy:data']);
});

You don't have to parse it for data extraction, simply use regexp :

  str = "<yyy:response xmlns:xxx='http://example.com'> <yyy:success><yyy:data>some-value</yyy:data> </yyy:success></yyy:response>";
  var re = new RegExp("<yyy:data>(.*?)</yyy:data?>", "gmi");

  while(res = re.exec(str)){ console.log(res[1])}

 // some-value