Fix linkquality N/A when refreshing frontend. https://github.com/Koenkk/zigbee2mqtt/issues/4942

lib/extension/frontend.js

@@ -109,6 +109,10 @@ class Frontend extends Extension {
                 payload.last_seen = utils.formatDate(resolvedEntity.device.lastSeen, lastSeen);
             }
 
+            if (resolvedEntity.device.linkquality !== undefined) {
+                payload.linkquality = resolvedEntity.device.linkquality;
+            }
+
             ws.send(stringify({topic: resolvedEntity.name, payload}));
         }
     }

test/frontend.test.js

@@ -6,6 +6,7 @@ const settings = require('../lib/util/settings');
 const Controller = require('../lib/controller');
 const stringify = require('json-stable-stringify-without-jsonify');
 const flushPromises = () => new Promise(setImmediate);
+const zigbeeHerdsman = require('./stub/zigbeeHerdsman');
 jest.spyOn(process, 'exit').mockImplementation(() => {});
 
 const mockHTTP = {
@@ -87,6 +88,11 @@ describe('Frontend', () => {
         settings.set(['experimental'], {new_api: true});
         settings.set(['frontend'], {port: 8081});
         settings.set(['homeassistant'], true);
+        zigbeeHerdsman.devices.bulb.linkquality = 10;
+    });
+
+    afterEach(async() => {
+        delete zigbeeHerdsman.devices.bulb.linkquality;
     });
 
     it('Start/stop', async () => {