How to use the oauth.OAuth function in oauth

exports.setConfig = function(cfg){
  config = cfg;
  oauth = new OAuth.OAuth(
    REQUEST_URL,
    ACCESS_URL,
    config.xeroConsumerKey,
    config.xeroConsumerSecret,
    '1.0A',
    null,
    'HMAC-SHA1',
    null,
    customHeaders
  );
  // This is important - Xero will redirect to this URL after successful authentication
  // and provide the request token as query parameters
  oauth._authorize_callback = config.xeroCallbackUrl;
};

return new Promise((resolve, reject) => {
        let oa = new oauth(this.options.oauth_request_url, this.options.oauth_access_url, this.options.key, this.options.secret, this.options.oauth_version, this.options.callback, this.options.oauth_encryption);
        oa.getOAuthRequestToken((error, oauthToken, oauthTokenSecret, results) => {
          if (error) {
            return reject(`Error getting OAuth request token : ${JSON.stringify(error)}`, 500);
          } else {
            // assemble goodreads URL
            let url = `https://goodreads.com/oauth/authorize?oauth_token=${oauthToken}&oauth_callback=${oa._authorize_callback}`;
            return resolve({oauthToken, oauthTokenSecret, url});
          }
        })
      })
    }

apiBase.prototype.authRequest = function apiBaseAuthRequest(callback)
{
  // cheatsheet: requestUrl, accessUrl, consumerKey, consumerSecret, version, authorize_callback, signatureMethod
  this.OA = new oauth
  (
    this.OAuth.request,
    this.OAuth.access,
    this.OAuth.key,
    this.OAuth.secret,
    this.OAuth.version || Defaults.version,
    'http://'+this.Data.callbackHost+this.OAuth.callback,
    this.OAuth.signature || Defaults.signature
  );

  // change header separator to make 500px work with it.
  this.OA._oauthParameterSeperator = ', ';

  // request token
  this.OA.getOAuthRequestToken(callback);
}

exports.listAccounts = function (req, res){
	var oa = new OAuth(	req.session.oa._requestUrl,
						req.session.oa._accessUrl,
						req.session.oa._consumerKey,
						req.session.oa._consumerSecret,
						req.session.oa._version,
						req.session.oa._authorize_callback,
						req.session.oa._signatureMethod
					);
	
	oa.getProtectedResource(
		global.url.etrade[global.server].accounts.list,
		"GET",
		req.session.oauth_access_token,
		req.session.oauth_access_token_secret,
		function (error, data, response) {	
			console.log(data);
			var feed = JSON.parse(data);

if (typeof process.env.SPACE_CLAW_DEV !== 'undefined') {
  config.host = 'spaceclaw.com';
  config.port = '8080';
  config.admin = '61091860@N00';
  config.backdoor = secrets.backdoor_passphrase;
}

app.use(express.static(__dirname + '/public'));
app.use(express.cookieParser());
app.use(express.session({ secret: secrets.express_session_secret, store: new RedisStore }));
app.use(express.bodyParser());

app.set('views', __dirname + '/public');
app.engine('html', require('ejs').renderFile);

var oa = new OAuth("http://www.flickr.com/services/oauth/request_token",
  "http://www.flickr.com/services/oauth/access_token",
  secrets.flickr_api_key,
  secrets.flickr_api_secret,
  "1.0A",
  "http://" + config.host + (typeof config.port !== 'undefined' ? ':' + config.port : '') + "/callback",
  "HMAC-SHA1");

app.get('/', function(req, res){
  res.render('index.html');
});

app.get('/loggedin', function(req, res){
  res.render('loggedin.html');
});

app.get('/login/:sessionId/', function(req, res){

function initOAuth(callbackURL) {
    if (!callbackURL) logWarning('Warning: You have passed no callbackURL.', 'initOAuth()');

    const requestURL = `${URL}/oauth/request_token`;
    const accessURL = `${URL}/oauth/access_token`;
    const version = '1.0';
    const encryption = 'HMAC-SHA1';

    OAUTH = new OAuth(requestURL, accessURL, KEY, SECRET, version, callbackURL, encryption);
  };

'use strict'

const { OAuth } = require('oauth')
const request = require('superagent')

const logger = require('./../logger')
const {
  getWebhookURL,
  getTwitterWebhookConsumerKey,
  getTwitterWebhookConsumerSecret
} = require('../utils/hooks')

const oauth = new OAuth(
  'https://api.twitter.com/oauth/request_token',
  'https://api.twitter.com/oauth/access_token',
  getTwitterWebhookConsumerKey(),
  getTwitterWebhookConsumerSecret(),
  '1.0',
  null,
  'HMAC-SHA1'
)

const HOOK_ENV = process.env.TWITTER_WEBHOOK_ENV || 'dev'

/**
 * List all registered webhooks
 * @param {String} oAuthToken
 * @param {String} oAuthAccessTokenSecret
 */

var express = require('express')
  , passport = require('passport')
  , htts = require('https')
  , OAuth = require('oauth').OAuth
  , crypto = require('crypto')
  , util = require('util')
  , fs = require('fs')
  , LocalStrategy = require('passport-local').Strategy;
  
//var couchkeys = require('./couchkeys');

/**
 * Prepare to use Twitter as a possible OAuth
 */
var twitterkeys = require('./twitterkeys');
var oa = new OAuth(
    "https://api.twitter.com/oauth/request_token",
    "https://api.twitter.com/oauth/access_token",
    twitterkeys.consumerKey,
    twitterkeys.consumerSecret,
    "1.0",
    "https://ifield.fieldlinguist.com/auth/twitter/callback",
    "HMAC-SHA1"
  );



var httpsOptions ={
  key: fs.readFileSync('ifield.key'),
  cert: fs.readFileSync('ifield.crt')};
var app = express.createServer(httpsOptions);

return function (req, res, next) {
		var oauth = new OAuth('https://vimeo.com/oauth/request_token',
							'https://vimeo.com/oauth/access_token',
							config.services.vimeo.clientId,
							config.services.vimeo.clientSecret,
							'1.0',
							null,
							'HMAC-SHA1');

		var requestToken = req.query.oauth_token;
		var verifier = req.query.oauth_verifier;

		users.findByRequestToken('vimeoRequestToken', requestToken, userFound);

		function userFound (err, user) {
			if (err) {
				return next(err);
			}

function consumer () {
    return new oauth.OAuth(
        _apiHost + "/oauth/request_token", _apiSecureHost + "/oauth/access_token",
        _twitterConsumerKey, _twitterConsumerSecret, "1.0A", _host + _callbackPath, "HMAC-SHA1");
}