networkInterfaces() added default property and parameter

lib/network.js

@@ -692,17 +692,29 @@ function testVirtualNic(iface, ifaceName, mac) {
   } else { return false; }
 }
 
-function networkInterfaces(callback, rescan) {
+function networkInterfaces(callback, rescan, defaultString) {
+
+  if (typeof callback === 'string') {
+    defaultString = callback;
+    rescan = true;
+    callback = null;
+  }
 
   if (typeof callback === 'boolean') {
     rescan = callback;
     callback = null;
+    defaultString = '';
   }
   if (typeof rescan === 'undefined') {
     rescan = true;
   }
+  defaultString = defaultString || '';
+  defaultString = '' + defaultString;
+
   return new Promise((resolve) => {
     process.nextTick(() => {
+      const defaultInterface = getDefaultNetworkInterface();
+
       let ifaces = os.networkInterfaces();
 
       let result = [];
@@ -730,6 +742,7 @@ function networkInterfaces(callback, rescan) {
           result.push({
             iface: nic.iface,
             ifaceName: nic.iface,
+            default: nic.iface === defaultInterface,
             ip4: nic.ip4,
             ip4subnet: nic.ip4subnet || '',
             ip6: nic.ip6,
@@ -750,6 +763,14 @@ function networkInterfaces(callback, rescan) {
           });
         });
         _networkInterfaces = result;
+        if (defaultString.toLowerCase().indexOf('default') >= 0) {
+          result = result.filter(item => item.default);
+          if (result.length > 0) {
+            result = result[0];
+          } else {
+            result = [];
+          }
+        }
         if (callback) { callback(result); }
         resolve(result);
       }
@@ -863,6 +884,7 @@ function networkInterfaces(callback, rescan) {
               result.push({
                 iface,
                 ifaceName,
+                default: iface === defaultInterface,
                 ip4,
                 ip4subnet,
                 ip6,
@@ -884,6 +906,14 @@ function networkInterfaces(callback, rescan) {
             }
           }
           _networkInterfaces = result;
+          if (defaultString.toLowerCase().indexOf('default') >= 0) {
+            result = result.filter(item => item.default);
+            if (result.length > 0) {
+              result = result[0];
+            } else {
+              result = [];
+            }
+          }
           if (callback) { callback(result); }
           resolve(result);
         }
@@ -990,6 +1020,7 @@ function networkInterfaces(callback, rescan) {
                 result.push({
                   iface,
                   ifaceName,
+                  default: iface === defaultInterface,
                   ip4,
                   ip4subnet,
                   ip6,
@@ -1011,6 +1042,14 @@ function networkInterfaces(callback, rescan) {
               }
             }
             _networkInterfaces = result;
+            if (defaultString.toLowerCase().indexOf('default') >= 0) {
+              result = result.filter(item => item.default);
+              if (result.length > 0) {
+                result = result[0];
+              } else {
+                result = [];
+              }
+            }
             if (callback) { callback(result); }
             resolve(result);
           });