diff --git a/components/market.js b/components/market.js
index 15b1632..25049a4 100644
--- a/components/market.js
+++ b/components/market.js
@@ -14,7 +14,7 @@ SteamCommunity.prototype.getMarketApps = function(callback) {
 			return;
 		}
 
-		var $ = Cheerio.load(body);
+		let $ = Cheerio.load(body);
 		if ($('.market_search_game_button_group')) {
 			let apps = {};
 			$('.market_search_game_button_group a.game_button').each(function (i, element) {
diff --git a/components/profile.js b/components/profile.js
index 67b15b3..793af24 100644
--- a/components/profile.js
+++ b/components/profile.js
@@ -61,7 +61,7 @@ SteamCommunity.prototype.editProfile = function(settings, callback) {
 		}
 
 		let values = {
-			sessionID: self.getSessionID(),
+			sessionID: this.getSessionID(),
 			type: 'profileSave',
 			weblink_1_title: '',
 			weblink_1_url: '',
diff --git a/components/twofactor.js b/components/twofactor.js
index c02828d..490de26 100644
--- a/components/twofactor.js
+++ b/components/twofactor.js
@@ -1,68 +1,109 @@
 const SteamTotp = require('steam-totp');
 
 const SteamCommunity = require('../index.js');
+const Helpers = require('./helpers.js');
 
 const ETwoFactorTokenType = {
-	"None": 0,                  // No token-based two-factor authentication
-	"ValveMobileApp": 1,        // Tokens generated using Valve's special charset (5 digits, alphanumeric)
-	"ThirdParty": 2             // Tokens generated using literally everyone else's standard charset (6 digits, numeric). This is disabled.
+	None: 0,                  // No token-based two-factor authentication
+	ValveMobileApp: 1,        // Tokens generated using Valve's special charset (5 digits, alphanumeric)
+	ThirdParty: 2             // Tokens generated using literally everyone else's standard charset (6 digits, numeric). This is disabled.
 };
 
 SteamCommunity.prototype.enableTwoFactor = function(callback) {
-	var self = this;
-
-	this.getWebApiOauthToken(function(err, token) {
-		if(err) {
+	this.getWebApiOauthToken((err, token) => {
+		if (err) {
 			callback(err);
 			return;
 		}
 
-		self.httpRequestPost({
-			"uri": "https://api.steampowered.com/ITwoFactorService/AddAuthenticator/v1/",
-			"form": {
-				"steamid": self.steamID.getSteamID64(),
-				"access_token": token,
-				"authenticator_time": Math.floor(Date.now() / 1000),
-				"authenticator_type": ETwoFactorTokenType.ValveMobileApp,
-				"device_identifier": SteamTotp.getDeviceID(self.steamID),
-				"sms_phone_id": "1"
+		this.httpRequestPost({
+			uri: 'https://api.steampowered.com/ITwoFactorService/AddAuthenticator/v1/',
+			form: {
+				steamid: this.steamID.getSteamID64(),
+				access_token: token,
+				authenticator_time: Math.floor(Date.now() / 1000),
+				authenticator_type: ETwoFactorTokenType.ValveMobileApp,
+				device_identifier: SteamTotp.getDeviceID(this.steamID),
+				sms_phone_id: '1'
 			},
-			"json": true
-		}, function(err, response, body) {
+			json: true
+		}, (err, response, body) => {
 			if (err) {
 				callback(err);
 				return;
 			}
 
-			if(!body.response) {
-				callback(new Error("Malformed response"));
+			if (!body.response) {
+				callback(new Error('Malformed response'));
 				return;
 			}
 
-			if(body.response.status != 1) {
-				var error = new Error("Error " + body.response.status);
-				error.eresult = body.response.status;
-				callback(error);
-				return;
+			let err2 = Helpers.eresultError(body.response.status);
+			if (err2) {
+				return callback(err2);
 			}
 
 			callback(null, body.response);
-		}, "steamcommunity");
+		}, 'steamcommunity');
 	});
 };
 
 SteamCommunity.prototype.finalizeTwoFactor = function(secret, activationCode, callback) {
-	var attemptsLeft = 30;
-	var diff = 0;
+	let attemptsLeft = 30;
+	let diff = 0;
 
-	var self = this;
-	this.getWebApiOauthToken(function(err, token) {
-		if(err) {
+	const finalize = (token) => {
+		let code = SteamTotp.generateAuthCode(secret, diff);
+
+		this.httpRequestPost({
+			uri: 'https://api.steampowered.com/ITwoFactorService/FinalizeAddAuthenticator/v1/',
+			form: {
+				steamid: this.steamID.getSteamID64(),
+				access_token: token,
+				authenticator_code: code,
+				authenticator_time: Math.floor(Date.now() / 1000),
+				activation_code: activationCode
+			},
+			json: true
+		}, (err, response, body) => {
+			if (err) {
+				callback(err);
+				return;
+			}
+
+			if (!body.response) {
+				callback(new Error('Malformed response'));
+				return;
+			}
+
+			body = body.response;
+
+			if (body.server_time) {
+				diff = body.server_time - Math.floor(Date.now() / 1000);
+			}
+
+			if (body.status == SteamCommunity.EResult.TwoFactorActivationCodeMismatch) {
+				callback(new Error('Invalid activation code'));
+			} else if (body.want_more) {
+				attemptsLeft--;
+				diff += 30;
+
+				finalize(token);
+			} else if (!body.success) {
+				callback(Helpers.eresultError(body.status));
+			} else {
+				callback(null);
+			}
+		}, 'steamcommunity');
+	}
+
+	this.getWebApiOauthToken((err, token) => {
+		if (err) {
 			callback(err);
 			return;
 		}
 
-		SteamTotp.getTimeOffset(function(err, offset, latency) {
+		SteamTotp.getTimeOffset((err, offset, latency) => {
 			if (err) {
 				callback(err);
 				return;
@@ -72,89 +113,42 @@ SteamCommunity.prototype.finalizeTwoFactor = function(secret, activationCode, ca
 			finalize(token);
 		});
 	});
-
-	function finalize(token) {
-		var code = SteamTotp.generateAuthCode(secret, diff);
-
-		self.httpRequestPost({
-			"uri": "https://api.steampowered.com/ITwoFactorService/FinalizeAddAuthenticator/v1/",
-			"form": {
-				"steamid": self.steamID.getSteamID64(),
-				"access_token": token,
-				"authenticator_code": code,
-				"authenticator_time": Math.floor(Date.now() / 1000),
-				"activation_code": activationCode
-			},
-			"json": true
-		}, function(err, response, body) {
-			if (err) {
-				callback(err);
-				return;
-			}
-
-			if(!body.response) {
-				callback(new Error("Malformed response"));
-				return;
-			}
-
-			body = body.response;
-
-			if(body.server_time) {
-				diff = body.server_time - Math.floor(Date.now() / 1000);
-			}
-
-			if(body.status == 89) {
-				callback(new Error("Invalid activation code"));
-			} else if(body.want_more) {
-				attemptsLeft--;
-				diff += 30;
-
-				finalize(token);
-			} else if(!body.success) {
-				callback(new Error("Error " + body.status));
-			} else {
-				callback(null);
-			}
-		}, "steamcommunity");
-	}
 };
 
 SteamCommunity.prototype.disableTwoFactor = function(revocationCode, callback) {
-	var self = this;
-
-	this.getWebApiOauthToken(function(err, token) {
-		if(err) {
+	this.getWebApiOauthToken((err, token) => {
+		if (err) {
 			callback(err);
 			return;
 		}
 
-		self.httpRequestPost({
-			"uri": "https://api.steampowered.com/ITwoFactorService/RemoveAuthenticator/v1/",
-			"form": {
-				"steamid": self.steamID.getSteamID64(),
-				"access_token": token,
-				"revocation_code": revocationCode,
-				"steamguard_scheme": 1
+		this.httpRequestPost({
+			uri: 'https://api.steampowered.com/ITwoFactorService/RemoveAuthenticator/v1/',
+			form: {
+				steamid: this.steamID.getSteamID64(),
+				access_token: token,
+				revocation_code: revocationCode,
+				steamguard_scheme: 1
 			},
-			"json": true
-		}, function(err, response, body) {
+			json: true
+		}, (err, response, body) => {
 			if (err) {
 				callback(err);
 				return;
 			}
 
-			if(!body.response) {
-				callback(new Error("Malformed response"));
+			if (!body.response) {
+				callback(new Error('Malformed response'));
 				return;
 			}
 
-			if(!body.response.success) {
-				callback(new Error("Request failed"));
+			if (!body.response.success) {
+				callback(new Error('Request failed'));
 				return;
 			}
 
 			// success = true means it worked
 			callback(null);
-		}, "steamcommunity");
+		}, 'steamcommunity');
 	});
 };