How to use the oauth.OAuth2 function in oauth

var authorizationURL = spSiteUrl + SP_AUTH_PREFIX;
  var appRedirectURL = spSiteUrl + SP_REDIRECT_PREFIX;
  
  // check if there is a app token present
  if (spAppToken && spSiteUrl) {
    var token = eval(jwt.decode(spAppToken, '', true));
    var splitApptxSender = token.appctxsender.split("@");
    var sharepointServer = url.parse(spSiteUrl)
    var resource = splitApptxSender[0]+"/"+sharepointServer.host+"@"+splitApptxSender[1];
    var spappId = this._appId+"@"+splitApptxSender[1];
    var appctx = JSON.parse(token.appctx);
    var tokenServiceUri = url.parse(appctx.SecurityTokenServiceUri);
    var tokenURL = tokenServiceUri.protocol+'//'+tokenServiceUri.host+'/'+splitApptxSender[1]+tokenServiceUri.path;

    this._oauth2 = new OAuth2(spappId,  this._appSecret, '', authorizationURL, tokenURL);
    this._oauth2.getOAuthAccessToken(
        token.refreshtoken,
        {grant_type: 'refresh_token', refresh_token: token.refreshtoken, resource: resource},
        function (err, accessToken, refreshToken, params) {
            if (err) { return self.error(new InternalOAuthError('failed to obtain access token', err)); }
            if (!refreshToken)
              refreshToken = spAppToken;
              
            self._loadUserProfile(accessToken, spSiteUrl, function(err, profile) {
              if (err) { return self.error(err); };
            
              function verified(err, user, info) {
                if (err) { return self.error(err); }
                if (!user) { return self.fail(info); }
                self.success(user, info);
              }

callback: function() {

		var self = this;
		var req = self.req;
		var query = req.url.query;
		
		req.user.tokens  = {};

		if (query.error || !query.code) {
			self.failed (query.error_description || "token was not accepted");
		}

		var oa = new OAuth2(vkontakteConfig.appId,  vkontakteConfig.appSecret,  vkontakteConfig.baseUrl, vkontakteConfig.authorizeUrl, vkontakteConfig.accessTokenUrl);
		
		oa.getOAuthAccessToken(
			query.code,
			{
				redirect_uri: vkontakteConfig.callbackUrl
			},
			function(error, access_token, refresh_token, results){

				if (error || !access_token) {

					self.failed(error || 'Bad request!');

				} else {

					req.user.tokens.oauth_access_token = access_token;
					if (refresh_token) req.user.tokens.oauth_refresh_token = refresh_token;

'use strict';

var express = require('express');
var OAuth2 = require('oauth').OAuth2;

var OAUTH_KEY     = process.env.OAUTH_KEY;
var OAUTH_SECRET  = process.env.OAUTH_SECRET;
var BASEPATH      = 'https://gitter.im/';
var REDIRECT      = process.env.REDIRECT;

var auth = new OAuth2(OAUTH_KEY, OAUTH_SECRET, BASEPATH, 'login/oauth/authorize', 'login/oauth/token');

var login = (req, res) => {
  var url = auth.getAuthorizeUrl({
    redirect_uri: REDIRECT, 
    response_type: 'code'
  });
  res.redirect(url);
};

var callback = (req, res) => {
  var code = req.query.code;
  var params = {
    redirect_uri: REDIRECT, 
    grant_type: 'authorization_code'
  };

router.github = function(req, res) {
        var github = new oauth.OAuth2(
            config.github.client_id,
            config.github.client_secret,
            'https://github.com/login'
        );
        var redirect_uri = options.base_uri + url.parse(req.url).pathname;

        var code = req.param('code');
        if (req.session.oauth && req.session.oauth.github && code) {
            delete req.session.oauth.github;

            var params = {
                oauth2: github,
                code: code,
                redirect_uri: redirect_uri,
                get_url: 'http://github.com/api/v2/json/user/show',
                keyname: function(data) {

async function getFollowing(handle, consumerKey, consumerSecret) {
  const url = 'friends/list';

  const oauth2 = new OAuth2(
    consumerKey,
    consumerSecret,
    'https://api.twitter.com/',
    null,
    'oauth2/token',
    null
  );

  return new Promise(resolve => {
    oauth2.getOAuthAccessToken(
      '',
      {
        grant_type: 'client_credentials',
      },
      (error, accessToken) => {
        resolve(accessToken);

function fbOAuth2() {
  const appId = keyConverter(process.env.FB_APPIDS);
  const secret = keyConverter(process.env.FB_SECRETS);
  return new OAuth2(
    appId,
    secret,
    "",
    "https://www.facebook.com/dialog/oauth",
    "https://graph.facebook.com/oauth/access_token",
    null
  );
}

this.fetcher.tokenStore.getApplicationTokens( 'appdotnet', function( error, tokens ) {
        if( error ) {
            done( error );
        }
        else
        {
            var OAuth2 = require( 'oauth' ).OAuth2;
            this.oauth2 = new OAuth2( 
                tokens.clientID, 
                tokens.clientSecret, 
                "https://alpha.app.net", 
                "/oauth/authenticate", 
                "/oauth/access_token" );
            done();
        }
    });
}

async function getRawTweets(handle, consumerKey, consumerSecret) {
  const url = 'statuses/user_timeline';

  const oauth2 = new OAuth2(
    consumerKey,
    consumerSecret,
    'https://api.twitter.com/',
    null,
    'oauth2/token',
    null
  );

  return new Promise(resolve => {
    oauth2.getOAuthAccessToken(
      '',
      {
        grant_type: 'client_credentials',
      },
      (error, accessToken) => {
        resolve(accessToken);

_post : function (url) {
		var self = this;
		var req = this.req;
		var tokens = req.user.tokens;
		var msg = this.message;

		var oa = new OAuth2(
			facebookConfig.appId,
			facebookConfig.appSecret,
			facebookConfig.baseUrl
		);

		var post_headers= {
			'Content-Type': 'application/x-www-form-urlencoded'
		};
		var post_data = msg;

		oa._request(
			'POST', url,
			post_headers, post_data, req.user.tokens.oauth_access_token,
			function (error, data) {
				if (error) {
					self.failed(error);

function daumOAuth2() {
  const appId = keyConverter(process.env.DAUM_APPIDS);
  const secret = keyConverter(process.env.DAUM_SECRETS);
  return new OAuth2(
    appId,
    secret,
    "",
    "https://apis.daum.net/oauth2/authorize",
    "https://apis.daum.net/oauth2/token",
    null
  );
}