diff --git a/lib/extension/networkMap.js b/lib/extension/networkMap.js
index aa167e543..1fa420394 100644
--- a/lib/extension/networkMap.js
+++ b/lib/extension/networkMap.js
@@ -51,7 +51,7 @@ class NetworkMap {
             const friendlyName = friendlyDevice ? friendlyDevice.friendly_name : device.ieeeAddr;
 
             // Add friendly name
-            labels.push(friendlyName+":"+device.nwkAddr);
+            labels.push(`${friendlyName}:${device.nwkAddr}`);
 
             // Add the device type
             const deviceType = utils.correctDeviceType(device);