Unable to download file from Google Drive using API - node.js

I am trying to download a File from google drive using Google SDK API using node.js.

But I am unable to write/save file at server side - node.js

Code:-

var GoogleTokenProvider = require("refresh-token").GoogleTokenProvider,
    async = require('async'),
    fs = require("fs"),
    request = require('request'),
    _accessToken;

var _XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
var https = require('https');

const CLIENT_ID = "";
const CLIENT_SECRET = "";
const REFRESH_TOKEN = '';
const ENDPOINT_OF_GDRIVE = 'http://ift.tt/1yBdjZk';

async.waterfall([
        //-----------------------------
        // Obtain a new access token
        //-----------------------------
        function(callback) {
            var tokenProvider = new GoogleTokenProvider({
                'refresh_token': REFRESH_TOKEN,
                'client_id': CLIENT_ID,
                'client_secret': CLIENT_SECRET
            });
            tokenProvider.getToken(callback);
        },

        //--------------------------------------------
        // Retrieve the children in a specified folder
        // 
        // ref: http://ift.tt/1HKbrU3
        //-------------------------------------------
        function(accessToken, callback) {
            _accessToken = accessToken;
            request.get({
                'url': ENDPOINT_OF_GDRIVE + '/files?' + "q='root' in parents  and (mimeType = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document')",
                'qs': {
                    'access_token': accessToken
                }
            }, callback);
        },

        //----------------------------
        // Parse the response
        //----------------------------
        function(response, body, callback) {
            var list = JSON.parse(body);
            if (list.error) {
                return callback(list.error);
            }
            callback(null, list.items[0]);
        },

        //-------------------------------------------
        // Get the file information of the children.
        //
        // ref: http://ift.tt/Q3fmNw
        //-------------------------------------------
        function(children, callback) {

            var xhr = new _XMLHttpRequest();
            xhr.open('GET', children.downloadUrl);
            xhr.setRequestHeader('Authorization', 'Bearer ' + _accessToken);
            xhr.onload = function() {
                console.log("xhr.responseText", xhr.responseText)
                fs.writeFile("download.docx", xhr.responseText)
                callback(xhr.responseText);
            };
            xhr.onerror = function() {
                callback(null);
            };
            xhr.send();
        }
    ],
    function(err, results) {
        if (!err) {
            console.log(results);
        }
    });

I am getting this in console:- Content of xhr.responseText is something like that

��▬h��↕E6M��~��3�3∟�9�� � �►��/2�:���♂�4��]�♀I�R���►
$SB6Q���c↔��H�=;+
���►q�3Tdכ��@!T��hEl_�|�I�↨��h(�^:▬�[h̓D♠��f���♠*���ݾ��M→
�1⌂♦"N�↑�o�]�7U$��A6����♠�W��k`�f▬♫��K�Z�^‼�0{<Z�▼�]F�����

                             ���J♥A♀��♣�a�}7�
"���H�w"�♥���☺w♫̤ھ�� �P�^����O֛���;�<♠�aYՠ؛`G�kxm��PY�[��g
Gΰino�/<���<�1��ⳆA$>"f3��\�ȾT��∟I S�������W♥����Y

Please help me to know what is the format of the data I am getting from Drive Api and write it in which format so that I got a complete .docx file

Edit

I am open to use any method other than xmlRequest if it helps me downloading the file(.docx).

Bounty For:

A complete working example, which should be capable of downloading/saving/ a (.docx) file from Google Drive at Server using node.js API