diff --git a/README.md b/README.md
index 6616760..ca45807 100644
--- a/README.md
+++ b/README.md
@@ -47,7 +47,7 @@ The tool returns an array with objects, each object representing a network with
 
 * channel: WiFi channel
 * ssid: SSID of the network (if available)
-* mac: MAC Address of the network access point
+* mac: MAC Address of the network access point (if available, otherwise empty string)
 * rssi: signal strength
 
 In contrary to other wifi scanners no information about security is returned. This is due to the very different implementation
diff --git a/lib/airport.js b/lib/airport.js
index 1f48e40..894a0fe 100644
--- a/lib/airport.js
+++ b/lib/airport.js
@@ -20,11 +20,11 @@ function parseOutput(str, callback) {
     let lines = str.split('\n');
 
     for (let i = 1, l = lines.length; i < l; i++) {
-      if (lines[i] == '') continue;
-      let elements = lines[i].substr(51).split(/[ ]+/);
+      if (lines[i] === '') continue;
+      let elements = lines[i].substring(51).split(/[ ]+/);
       wifis.push({
-        'ssid'   : lines[i].substr(0,32).trim(),
-        'mac'    : lines[i].substr(33,17).trim(),
+        'ssid'   : lines[i].substring(0, 32).trim(),
+        'mac'    : '',  // There is no more mac on a mac
         'channel': parseInt(elements[1].trim(), 10),
         'rssi'   : parseInt(elements[0].trim(), 10)
       });
diff --git a/package.json b/package.json
index 931f289..80f25d8 100644
--- a/package.json
+++ b/package.json
@@ -35,12 +35,12 @@
     "test": "mocha test"
   },
   "dependencies": {
-    "async": "3.1.0",
-    "lodash": "4.17.15"
+    "async": "3.2.4",
+    "lodash": "4.17.21"
   },
   "devDependencies": {
-    "grunt": "^1.0.3",
+    "grunt": "1.5.3",
     "grunt-bump": "0.8.0",
-    "mocha": "6.2.0"
+    "mocha": "10.2.0"
   }
 }