diff --git a/src/topics/tags.js b/src/topics/tags.js
index daab4e5f77..8862d8d4d3 100644
--- a/src/topics/tags.js
+++ b/src/topics/tags.js
@@ -17,6 +17,11 @@ const utils = require('../utils');
 const batch = require('../batch');
 const cache = require('../cache');
 
+function extractTagValues(tags) {
+	return tags.map(tagItem => tagItem.value);
+}
+
+
 module.exports = function (Topics) {
 	Topics.createTags = async function (tags, tid, timestamp) {
 		if (!Array.isArray(tags) || !tags.length) {
@@ -158,7 +163,7 @@ module.exports = function (Topics) {
 
 			// update 'tags' field in topic hash
 			topicData.forEach((topic) => {
-				topic.tags = topic.tags.map(tagItem => tagItem.value);
+				topic.tags = extractTagValues(topic.tags);
 				const index = topic.tags.indexOf(tag);
 				if (index !== -1) {
 					topic.tags.splice(index, 1, newTagName);