refactor: extract MQTT_RETAINED_STATE_OPTIONS + named regex constants

Two small DRY wins flagged by /simplify but skipped earlier:

1. The literal { retain: true, qos: 0 } appeared at 16 callsites across
   haDiscovery.js, haBridgeDiagnostics.js, staleDeviceDetector.js,
   mqttCommandRouter.js, and cgateWebBridge.js. Replace with a frozen
   MQTT_RETAINED_STATE_OPTIONS constant in src/constants.js. The frozen
   object prevents accidental mutation of a now-shared reference.

2. Two regexes in commandResponseProcessor.js — the C-Gate timestamp
   prefix and the network-path extractor — were inline. Move them to
   named module-scope constants (CGATE_TIMESTAMP_PREFIX,
   CGATE_NETWORK_PATH) so the intent is visible at the callsite and
   the patterns can be referenced by future code without copy-paste.

Also drops a now-redundant local `opts` alias in staleDeviceDetector
that just aliased the literal.

No behaviour change. Full suite 1199/1199 passing, lint clean.

Author: dougrathbone

src/cgateWebBridge.js

@@ -15,6 +15,7 @@ const HaBridgeDiagnostics = require('./haBridgeDiagnostics');
 const StaleDeviceDetector = require('./staleDeviceDetector');
 const { createLogger } = require('./logger');
 const { LineProcessor } = require('./lineProcessor');
+const { MQTT_RETAINED_STATE_OPTIONS } = require('./constants');
 
 /**
  * Main bridge class that connects C-Gate (Clipsal C-Bus automation system) to MQTT.
@@ -140,7 +141,7 @@ class CgateWebBridge {
         };
 
         // MQTT options
-        this._mqttOptions = this.settings.retainreads ? { retain: true, qos: 0 } : { qos: 0 };
+        this._mqttOptions = this.settings.retainreads ? MQTT_RETAINED_STATE_OPTIONS : { qos: 0 };
 
         // Label loader for custom device names (before EventPublisher so it can use type overrides)
         this.labelLoader = new LabelLoader(this.settings.cbus_label_file || null);

src/commandResponseProcessor.js

@@ -8,6 +8,11 @@ const {
     CGATE_RESPONSE_SYSTEM_EVENT
 } = require('./constants');
 
+// Strips C-Gate's leading async-event timestamp ("20260504-193110.569 ").
+const CGATE_TIMESTAMP_PREFIX = /^\d{8}-\d{6}\.\d+\s+/;
+// Extracts the numeric network id from a C-Gate object path "//PROJECT/254 ...".
+const CGATE_NETWORK_PATH = /\/\/[^/]+\/(\d+)\b/;
+
 /**
  * Handles processing of C-Gate command responses.
  * 
@@ -90,7 +95,7 @@ class CommandResponseProcessor {
         // Asynchronous notifications enabled by EVENT ON arrive on the command
         // port with this prefix; without stripping it the hyphen-first split
         // below would land in the date instead of the response code.
-        const stripped = (line || '').replace(/^\d{8}-\d{6}\.\d+\s+/, '');
+        const stripped = (line || '').replace(CGATE_TIMESTAMP_PREFIX, '');
 
         // C-Gate response codes are exactly 3 digits at the start of the line,
         // followed by either '-' (e.g. "200-OK") or ' ' (e.g. "742 //PROJECT
@@ -200,7 +205,7 @@ class CommandResponseProcessor {
             this.logger.debug(`C-Gate system event 742 (no action): ${data}`);
             return;
         }
-        const match = data.match(/\/\/[^/]+\/(\d+)\b/);
+        const match = data.match(CGATE_NETWORK_PATH);
         if (!match) {
             this.logger.debug(`C-Gate system event 742 (Network created, but no network id parsed): ${data}`);
             return;

src/constants.js

@@ -44,6 +44,11 @@ const MQTT_TOPIC_SUFFIX_HVAC_FAN_MODE = 'fan_mode';               // Fan speed/m
 const MQTT_TOPIC_STATUS = 'hello/cgateweb';
 const MQTT_TOPIC_MANUAL_TRIGGER = `${MQTT_TOPIC_PREFIX_WRITE}/bridge/announce`;
 
+// Default publish options for retained state topics (HA Discovery configs,
+// device states, diagnostics). Frozen so callers can't accidentally mutate
+// the shared object.
+const MQTT_RETAINED_STATE_OPTIONS = Object.freeze({ retain: true, qos: 0 });
+
 // MQTT Payloads
 const MQTT_PAYLOAD_STATUS_ONLINE = 'Online';
 const MQTT_PAYLOAD_STATUS_OFFLINE = 'Offline';
@@ -168,6 +173,7 @@ module.exports = {
     MQTT_TOPIC_SUFFIX_HVAC_FAN_MODE,
     MQTT_TOPIC_STATUS,
     MQTT_TOPIC_MANUAL_TRIGGER,
+    MQTT_RETAINED_STATE_OPTIONS,
     MQTT_PAYLOAD_STATUS_ONLINE,
     MQTT_PAYLOAD_STATUS_OFFLINE,
     MQTT_STATE_ON,

src/haBridgeDiagnostics.js

@@ -1,6 +1,6 @@
 const fs = require('fs');
 const { createLogger } = require('./logger');
-const { MQTT_TOPIC_STATUS, entityIdFields, HA_COMPONENT_SENSOR, HA_COMPONENT_BINARY_SENSOR, HA_DEVICE_VIA } = require('./constants');
+const { MQTT_TOPIC_STATUS, MQTT_RETAINED_STATE_OPTIONS, entityIdFields, HA_COMPONENT_SENSOR, HA_COMPONENT_BINARY_SENSOR, HA_DEVICE_VIA } = require('./constants');
 
 const CGATE_VERSION_FILE = '/data/cgate/.version';
 
@@ -90,7 +90,7 @@ class HaBridgeDiagnostics {
                     model: 'Bridge Diagnostics'
                 }
             };
-            this._publish(topic, JSON.stringify(payload), { retain: true, qos: 0 });
+            this._publish(topic, JSON.stringify(payload), MQTT_RETAINED_STATE_OPTIONS);
         }
     }
 
@@ -124,7 +124,7 @@ class HaBridgeDiagnostics {
 
         for (const [key, value] of Object.entries(values)) {
             const topic = `cbus/read/bridge/diagnostics/${key}/state`;
-            this._publish(topic, String(value), { retain: true, qos: 0 });
+            this._publish(topic, String(value), MQTT_RETAINED_STATE_OPTIONS);
         }
 
         // Publish consolidated JSON stats for monitoring dashboards
@@ -156,7 +156,7 @@ class HaBridgeDiagnostics {
             } : null,
             cgate_version: cgateVersion
         };
-        this._publish('cbus/read/bridge/stats', JSON.stringify(stats), { retain: true, qos: 0 });
+        this._publish('cbus/read/bridge/stats', JSON.stringify(stats), MQTT_RETAINED_STATE_OPTIONS);
     }
 }
 

src/haDiscovery.js

@@ -27,6 +27,7 @@ const {
     MQTT_COMMAND_STOP,
     MQTT_TOPIC_SUFFIX_DISCOVERY_STATUS,
     MQTT_TOPIC_STATUS,
+    MQTT_RETAINED_STATE_OPTIONS,
     HA_COMPONENT_LIGHT,
     HA_COMPONENT_BUTTON,
     HA_COMPONENT_CLIMATE,
@@ -346,7 +347,7 @@ class HaDiscovery {
             }
         };
 
-        this._publish(configTopic, JSON.stringify(payload), { retain: true, qos: 0 });
+        this._publish(configTopic, JSON.stringify(payload), MQTT_RETAINED_STATE_OPTIONS);
         entry.configPublished = true;
     }
 
@@ -373,7 +374,7 @@ class HaDiscovery {
         entry.status = status;
 
         const stateTopic = `${MQTT_TOPIC_PREFIX_READ}/${networkKey}///${MQTT_TOPIC_SUFFIX_DISCOVERY_STATUS}`;
-        this._publish(stateTopic, status, { retain: true, qos: 0 });
+        this._publish(stateTopic, status, MQTT_RETAINED_STATE_OPTIONS);
         this.logger.debug(`Discovery status for network ${networkKey}: ${previous || 'init'} -> ${status}`);
     }
 
@@ -458,7 +459,7 @@ class HaDiscovery {
                 this._publish(
                     `${MQTT_TOPIC_PREFIX_READ}/${networkForTree}///tree`,
                     JSON.stringify(result),
-                    { retain: true, qos: 0 }
+                    MQTT_RETAINED_STATE_OPTIONS
                 );
 
                 // Generate HA Discovery messages
@@ -541,7 +542,7 @@ class HaDiscovery {
         for (const topic of this._publishedTopics) {
             if (topic.includes(`/${networkUniqueIdPrefix}`) && !this._currentRunTopics.has(topic)) {
                 this.logger.debug(`Clearing stale discovery topic: ${topic}`);
-                this._publish(topic, '', { retain: true, qos: 0 });
+                this._publish(topic, '', MQTT_RETAINED_STATE_OPTIONS);
             }
         }
 
@@ -621,7 +622,7 @@ class HaDiscovery {
                     // (e.g. first run saw it as a light; this run sees the type override).
                     const uniqueId = `cgateweb_${networkId}_${appId}_${groupId}`;
                     const staleTopic = `${this.settings.ha_discovery_prefix}/${HA_COMPONENT_LIGHT}/${uniqueId}/${HA_DISCOVERY_SUFFIX}`;
-                    this._publish(staleTopic, '', { retain: true, qos: 0 });
+                    this._publish(staleTopic, '', MQTT_RETAINED_STATE_OPTIONS);
                     // Ensure the stale light topic is not retained in _publishedTopics
                     this._publishedTopics.delete(staleTopic);
                     return;
@@ -671,7 +672,7 @@ class HaDiscovery {
                 }
             };
 
-            this._publish(discoveryTopic, JSON.stringify(payload), { retain: true, qos: 0 });
+            this._publish(discoveryTopic, JSON.stringify(payload), MQTT_RETAINED_STATE_OPTIONS);
             if (this._currentRunTopics) this._currentRunTopics.add(discoveryTopic);
             this.discoveryCount++;
         });
@@ -796,7 +797,7 @@ class HaDiscovery {
             }
         };
 
-        this._publish(discoveryTopic, JSON.stringify(payload), { retain: true, qos: 0 });
+        this._publish(discoveryTopic, JSON.stringify(payload), MQTT_RETAINED_STATE_OPTIONS);
         this.discoveryCount++;
     }
 
@@ -865,7 +866,7 @@ class HaDiscovery {
             }
         };
 
-        this._publish(discoveryTopic, JSON.stringify(payload), { retain: true, qos: 0 });
+        this._publish(discoveryTopic, JSON.stringify(payload), MQTT_RETAINED_STATE_OPTIONS);
         if (this._currentRunTopics) this._currentRunTopics.add(discoveryTopic);
         this.discoveryCount++;
 
@@ -909,7 +910,7 @@ class HaDiscovery {
             }
         };
 
-        this._publish(discoveryTopic, JSON.stringify(payload), { retain: true, qos: 0 });
+        this._publish(discoveryTopic, JSON.stringify(payload), MQTT_RETAINED_STATE_OPTIONS);
         this.discoveryCount++;
     }
 
@@ -942,7 +943,7 @@ class HaDiscovery {
             }
         };
 
-        this._publish(discoveryTopic, JSON.stringify(payload), { retain: true, qos: 0 });
+        this._publish(discoveryTopic, JSON.stringify(payload), MQTT_RETAINED_STATE_OPTIONS);
         this.discoveryCount++;
     }
 

src/mqttCommandRouter.js

@@ -5,6 +5,7 @@ const { createLogger } = require('./logger');
 const {
     MQTT_TOPIC_MANUAL_TRIGGER,
     MQTT_TOPIC_PREFIX_READ,
+    MQTT_RETAINED_STATE_OPTIONS,
     MQTT_TOPIC_SUFFIX_LEVEL,
     MQTT_TOPIC_SUFFIX_POSITION,
     MQTT_CMD_TYPE_GETALL,
@@ -462,7 +463,7 @@ class MqttCommandRouter extends EventEmitter {
             ? durationMs
             : (this.settings.cover_ramp_duration_ms || 5000);
 
-        const mqttOptions = this.settings.retainreads ? { retain: true, qos: 0 } : { qos: 0 };
+        const mqttOptions = this.settings.retainreads ? MQTT_RETAINED_STATE_OPTIONS : { qos: 0 };
         const topicBase = `${MQTT_TOPIC_PREFIX_READ}/${network}/${application}/${group}`;
 
         this._coverRampTracker.startRamp(key, startLevel, targetLevel, duration, (level) => {

src/staleDeviceDetector.js

@@ -1,5 +1,5 @@
 const { createLogger } = require('./logger');
-const { MQTT_TOPIC_STATUS, entityIdFields, HA_COMPONENT_SENSOR, HA_DEVICE_VIA } = require('./constants');
+const { MQTT_TOPIC_STATUS, MQTT_RETAINED_STATE_OPTIONS, entityIdFields, HA_COMPONENT_SENSOR, HA_DEVICE_VIA } = require('./constants');
 
 /**
  * Periodically checks for C-Bus devices that have not reported a state change
@@ -121,16 +121,15 @@ class StaleDeviceDetector {
      */
     _publishStaleCount(count, staleDevices) {
         const thresholdHours = Math.max(1, Number(this.settings.stale_device_threshold_hours) || 24);
-        const opts = { retain: true, qos: 0 };
 
-        this.mqttClient.publish('cbus/bridge/stale_devices', String(count), opts);
+        this.mqttClient.publish('cbus/bridge/stale_devices', String(count), MQTT_RETAINED_STATE_OPTIONS);
 
         const attributes = {
             stale_devices: staleDevices,
             threshold_hours: thresholdHours,
             checked_at: new Date().toISOString()
         };
-        this.mqttClient.publish('cbus/bridge/stale_devices_detail', JSON.stringify(attributes), opts);
+        this.mqttClient.publish('cbus/bridge/stale_devices_detail', JSON.stringify(attributes), MQTT_RETAINED_STATE_OPTIONS);
     }
 
     /**
@@ -159,7 +158,7 @@ class StaleDeviceDetector {
                 model: 'Bridge Diagnostics'
             }
         };
-        this.mqttClient.publish(topic, JSON.stringify(payload), { retain: true, qos: 0 });
+        this.mqttClient.publish(topic, JSON.stringify(payload), MQTT_RETAINED_STATE_OPTIONS);
     }
 }