Issue with parsing using xml2js

I have an xml in which tag name contains colon(:) It looks something like this:

<samlp:Response>
data
</samlp:Response>

I am using following code to parse this xml to json but can't use it because the tag name contains colon.

var xml2js = require('xml2js');
var parser = new xml2js.Parser();
var fs = require('fs');

    fs.readFile(
  filePath,
  function(err,data){
    if(!err){
      parser.parseString(data, function (err, result) {
        //Getting a linter warning/error at this point
        console.log(result.samlp:Response);
      });
    }else{
      callback('error while parsing assertion'+err);
    }
  }
);

};

Error:

events.js:161
      throw er; // Unhandled 'error' event
      ^

TypeError: Cannot read property 'Response' of undefined

How can I parse this XML successfully because changing the contents of my xml?

via nitinsh99