getDeviceIP: refactor

src/data/errors.js

@@ -11,6 +11,7 @@ const errors = {
 const customErrors = {
   ch404: 'Device channel does not exist',
   unknown: 'An unknown error occurred',
+  noARP: 'No ARP information found. You need to generate the ARP file.',
   noDevice: 'No device found',
   noDevices: 'No devices found',
   noPower: 'No power usage data found',

src/mixins/getDeviceIP.js

@@ -1,3 +1,5 @@
+const errors = require('../data/errors');
+
 module.exports = {
   /**
    * Get local IP address from a given MAC
@@ -6,10 +8,16 @@ module.exports = {
    * @returns {Promise<string>}
    */
   getDeviceIP(device) {
-    const mac = device.extra.extra.staMac;
+    if (!this.arpTable) {
+      throw new Error(errors.noARP);
+    }
+
+    const mac = device.extra.staMac;
+
     const arpItem = this.arpTable.find(
-      item => item.mac.toLowerCase() === mac.toLowerCase()
+      (item) => item.mac.toLowerCase() === mac.toLowerCase()
     );
+
     return arpItem.ip;
   },
 };