diff --git a/components/helpers.js b/components/helpers.js
index 5c3f705..0dd0e6c 100644
--- a/components/helpers.js
+++ b/components/helpers.js
@@ -39,15 +39,16 @@ exports.decodeSteamTime = function(time) {
 /**
  * Get an Error object for a particular EResult
  * @param {int} eresult
+ * @param {string} [message] - If eresult is a failure code and message exists, this message will be used in the Error object instead
  * @returns {null|Error}
  */
-exports.eresultError = function(eresult) {
-	if (eresult == EResult.OK) {
+exports.eresultError = function(eresult, message) {
+	if (!eresult || eresult == EResult.OK) {
 		// no error
 		return null;
 	}
 
-	let err = new Error(EResult[eresult] || ("Error " + eresult));
+	let err = new Error(message || EResult[eresult] || ("Error " + eresult));
 	err.eresult = eresult;
 	return err;
 };
diff --git a/components/market.js b/components/market.js
index a56c56e..15b1632 100644
--- a/components/market.js
+++ b/components/market.js
@@ -8,8 +8,7 @@ const Helpers = require('./helpers.js');
  * @param {function} callback - First argument is null|Error, second is an object of appid => name
  */
 SteamCommunity.prototype.getMarketApps = function(callback) {
-	var self = this;
-	this.httpRequest('https://steamcommunity.com/market/', function (err, response, body) {
+	this.httpRequest('https://steamcommunity.com/market/', (err, response, body) => {
 		if (err) {
 			callback(err);
 			return;
@@ -19,17 +18,17 @@ SteamCommunity.prototype.getMarketApps = function(callback) {
 		if ($('.market_search_game_button_group')) {
 			let apps = {};
 			$('.market_search_game_button_group a.game_button').each(function (i, element) {
-				var e = Cheerio.load(element);
-				var name = e('.game_button_game_name').text().trim();
-				var url = element.attribs.href;
-				var appid = url.substr(url.indexOf('=') + 1);
+				let e = Cheerio.load(element);
+				let name = e('.game_button_game_name').text().trim();
+				let url = element.attribs.href;
+				let appid = url.substr(url.indexOf('=') + 1);
 				apps[appid] = name;
 			});
 			callback(null, apps);
 		} else {
-			callback(new Error("Malformed response"));
+			callback(new Error('Malformed response'));
 		}
-	}, "steamcommunity");
+	}, 'steamcommunity');
 };
 
 /**
@@ -40,34 +39,32 @@ SteamCommunity.prototype.getMarketApps = function(callback) {
  */
 SteamCommunity.prototype.getGemValue = function(appid, assetid, callback) {
 	this._myProfile({
-		"endpoint": "ajaxgetgoovalue/",
-		"qs": {
-			"sessionid": this.getSessionID(),
-			"appid": appid,
-			"contextid": 6,
-			"assetid": assetid
+		endpoint: 'ajaxgetgoovalue/',
+		qs: {
+			sessionid: this.getSessionID(),
+			appid: appid,
+			contextid: 6,
+			assetid: assetid
 		},
-		"checkHttpError": false,
-		"json": true
+		checkHttpError: false,
+		json: true
 	}, null, (err, res, body) => {
 		if (err) {
 			callback(err);
 			return;
 		}
 
-		if (body.success && body.success != SteamCommunity.EResult.OK) {
-			let err = new Error(body.message || SteamCommunity.EResult[body.success]);
-			err.eresult = err.code = body.success;
-			callback(err);
-			return;
+		let err2 = Helpers.eresultError(body.success, body.message);
+		if (err2) {
+			return callback(err2);
 		}
 
 		if (!body.goo_value || !body.strTitle) {
-			callback(new Error("Malformed response"));
+			callback(new Error('Malformed response'));
 			return;
 		}
 
-		callback(null, {"promptTitle": body.strTitle, "gemValue": parseInt(body.goo_value, 10)});
+		callback(null, {promptTitle: body.strTitle, gemValue: parseInt(body.goo_value, 10)});
 	});
 };
 
@@ -80,34 +77,32 @@ SteamCommunity.prototype.getGemValue = function(appid, assetid, callback) {
  */
 SteamCommunity.prototype.turnItemIntoGems = function(appid, assetid, expectedGemsValue, callback) {
 	this._myProfile({
-		"endpoint": "ajaxgrindintogoo/",
-		"json": true,
-		"checkHttpError": false
+		endpoint: 'ajaxgrindintogoo/',
+		json: true,
+		checkHttpError: false
 	}, {
-		"appid": appid,
-		"contextid": 6,
-		"assetid": assetid,
-		"goo_value_expected": expectedGemsValue,
-		"sessionid": this.getSessionID()
+		appid: appid,
+		contextid: 6,
+		assetid: assetid,
+		goo_value_expected: expectedGemsValue,
+		sessionid: this.getSessionID()
 	}, (err, res, body) => {
 		if (err) {
 			callback(err);
 			return;
 		}
 
-		if (body.success && body.success != SteamCommunity.EResult.OK) {
-			let err = new Error(body.message || SteamCommunity.EResult[body.success]);
-			err.eresult = err.code = body.success;
-			callback(err);
+		let err2 = Helpers.eresultError(body.success, body.message);
+		if (err2) {
+			return callback(err2);
+		}
+
+		if (!body['goo_value_received '] || !body.goo_value_total) { // lol valve, that trailing space is real
+			callback(new Error('Malformed response'));
 			return;
 		}
 
-		if (!body['goo_value_received '] || !body.goo_value_total) { // lol valve
-			callback(new Error("Malformed response"));
-			return;
-		}
-
-		callback(null, {"gemsReceived": parseInt(body['goo_value_received '], 10), "totalGems": parseInt(body.goo_value_total, 10)});
+		callback(null, {gemsReceived: parseInt(body['goo_value_received '], 10), totalGems: parseInt(body.goo_value_total, 10)});
 	})
 };
 
@@ -119,28 +114,26 @@ SteamCommunity.prototype.turnItemIntoGems = function(appid, assetid, expectedGem
  */
 SteamCommunity.prototype.openBoosterPack = function(appid, assetid, callback) {
 	this._myProfile({
-		"endpoint": "ajaxunpackbooster/",
-		"json": true,
-		"checkHttpError": false
+		endpoint: 'ajaxunpackbooster/',
+		json: true,
+		checkHttpError: false
 	}, {
-		"appid": appid,
-		"communityitemid": assetid,
-		"sessionid": this.getSessionID()
+		appid: appid,
+		communityitemid: assetid,
+		sessionid: this.getSessionID()
 	}, (err, res, body) => {
 		if (err) {
 			callback(err);
 			return;
 		}
 
-		if (body.success && body.success != SteamCommunity.EResult.OK) {
-			let err = new Error(body.message || SteamCommunity.EResult[body.success]);
-			err.eresult = err.code = body.success;
-			callback(err);
-			return;
+		let err2 = Helpers.eresultError(body.success, body.message);
+		if (err2) {
+			return callback(err2);
 		}
 
 		if (!body.rgItems) {
-			callback(new Error("Malformed response"));
+			callback(new Error('Malformed response'));
 			return;
 		}
 
@@ -155,33 +148,31 @@ SteamCommunity.prototype.openBoosterPack = function(appid, assetid, callback) {
  */
 SteamCommunity.prototype.getGiftDetails = function(giftID, callback) {
 	this.httpRequestPost({
-		"uri": "https://steamcommunity.com/gifts/" + giftID + "/validateunpack",
-		"form": {
-			"sessionid": this.getSessionID()
+		uri: `https://steamcommunity.com/gifts/${giftID}/validateunpack`,
+		form: {
+			sessionid: this.getSessionID()
 		},
-		"json": true
+		json: true
 	}, (err, res, body) => {
 		if (err) {
 			callback(err);
 			return;
 		}
 
-		if (body.success && body.success != SteamCommunity.EResult.OK) {
-			let err = new Error(body.message || SteamCommunity.EResult[body.success]);
-			err.eresult = err.code = body.success;
-			callback(err);
-			return;
+		let err2 = Helpers.eresultError(body.success, body.message);
+		if (err2) {
+			return callback(err2);
 		}
 
 		if (!body.packageid || !body.gift_name) {
-			callback(new Error("Malformed response"));
+			callback(new Error('Malformed response'));
 			return;
 		}
 
 		callback(null, {
-			"giftName": body.gift_name,
-			"packageID": parseInt(body.packageid, 10),
-			"owned": body.owned
+			giftName: body.gift_name,
+			packageID: parseInt(body.packageid, 10),
+			owned: body.owned
 		});
 	});
 };
@@ -193,23 +184,20 @@ SteamCommunity.prototype.getGiftDetails = function(giftID, callback) {
  */
 SteamCommunity.prototype.redeemGift = function(giftID, callback) {
 	this.httpRequestPost({
-		"uri": "https://steamcommunity.com/gifts/" + giftID + "/unpack",
-		"form": {
-			"sessionid": this.getSessionID()
+		uri: `https://steamcommunity.com/gifts/${giftID}/unpack`,
+		form: {
+			sessionid: this.getSessionID()
 		},
-		"json": true
+		json: true
 	}, (err, res, body) => {
 		if (err) {
 			callback(err);
 			return;
 		}
 
-		if (body.success && body.success != SteamCommunity.EResult.OK) {
-
-			let err = new Error(body.message || SteamCommunity.EResult[body.success]);
-			err.eresult = err.code = body.success;
-			callback(err);
-			return;
+		let err2 = Helpers.eresultError(body.success, body.message);
+		if (err2) {
+			return callback(err2);
 		}
 
 		callback(null);