--- a/dom/wifi/DOMWifiManager.js
+++ b/dom/wifi/DOMWifiManager.js
@@ -155,17 +155,17 @@ DOMWifiManager.prototype = {
   },
 
   _convertWifiNetwork: function(aNetwork) {
     let network = aNetwork ? new this._window.MozWifiNetwork(aNetwork) : null;
     return network;
   },
 
   _convertWifiNetworks: function(aNetworks) {
-    let networks = [];
+    let networks = new this._window.Array();
     for (let i in aNetworks) {
       networks.push(this._convertWifiNetwork(aNetworks[i]));
     }
     return networks;
   },
 
   _convertConnection: function(aConn) {
     let conn = aConn ? new MozWifiConnection(aConn) : null;