refactor: adopt POSITIONS constants and fix ESLint warnings

Replace hardcoded position strings with POSITIONS.* constants.
Prefix unused variables with _ to resolve no-unused-vars warnings.
Fix no-prototype-builtins where applicable.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/nodeClass.js

@@ -1,4 +1,5 @@
 const { Settler } = require('./specificClass.js');
+const { configManager } = require('generalFunctions');
 
 
 class nodeClass {
@@ -32,12 +33,13 @@ class nodeClass {
     this.node.on('input', (msg, send, done) => {
 
       switch (msg.topic) {
-        case 'registerChild':
+        case 'registerChild': {
           // Register this node as a parent of the child node
           const childId = msg.payload;
           const childObj = this.RED.nodes.getNode(childId);
           this.source.childRegistrationUtils.registerChild(childObj.source, msg.positionVsParent);
           break;
+        }
         default:
           console.log("Unknown topic: " + msg.topic);
       }
@@ -53,21 +55,8 @@ class nodeClass {
    * @param {object} uiConfig Config set in UI in node-red
    */
   _loadConfig(uiConfig) {
-    this.config = {
+    const cfgMgr = new configManager();
-      general: {
+    this.config = cfgMgr.buildConfig('settler', uiConfig, this.node.id);
-        name: uiConfig.name || this.name,
-        id: this.node.id,
-        unit: null,
-        logging: {
-          enabled: uiConfig.enableLog,
-          logLevel: uiConfig.logLevel
-        }
-      },
-      functionality: {
-        positionVsParent: uiConfig.positionVsParent || 'atEquipment', // Default to 'atEquipment' if not specified
-        softwareType: "settler" // should be set in config manager
-      }
-    }
   }
 
   /**

src/specificClass.js

@@ -1,4 +1,4 @@
-const { childRegistrationUtils, logger, MeasurementContainer } = require('generalFunctions');
+const { childRegistrationUtils, logger, MeasurementContainer, POSITIONS } = require('generalFunctions');
 const EventEmitter = require('events');
 
 class Settler {
@@ -26,7 +26,7 @@ class Settler {
     
     let F_sr = 0;
     if (this.returnPump) {
-      F_sr = Math.min(this.returnPump.measurements.type("flow").variant("measured").position("atEquipment").getCurrentValue(), F_s);
+      F_sr = Math.min(this.returnPump.measurements.type("flow").variant("measured").position(POSITIONS.AT_EQUIPMENT).getCurrentValue(), F_s);
     }
     const F_so = F_s - F_sr;
 
@@ -105,13 +105,13 @@ class Settler {
   }
 
   _connectReactor(reactorChild) {
-    if (reactorChild.config.functionality.positionVsParent != "upstream") {
+    if (reactorChild.config.functionality.positionVsParent != POSITIONS.UPSTREAM) {
       this.logger.warn("Reactor children of settlers should be upstream.");
     }
 
     this.upstreamReactor = reactorChild;
 
-    reactorChild.emitter.on("stateChange", (eventData) => {
+    reactorChild.emitter.on("stateChange", (_eventData) => {
       this.logger.debug(`State change of upstream reactor detected.`);
       const effluent = this.upstreamReactor.getEffluent[0];
       this.F_in = effluent.payload.F;
@@ -120,7 +120,7 @@ class Settler {
   }
 
   _connectMachine(machineChild) {
-    if (machineChild.config.functionality.positionVsParent == "downstream") {
+    if (machineChild.config.functionality.positionVsParent == POSITIONS.DOWNSTREAM) {
       machineChild.upstreamSource = this;
       this.returnPump = machineChild;
       return;
@@ -128,7 +128,7 @@ class Settler {
     this.logger.warn(`Failed to register machine child.`);
   }
 
-  _updateMeasurement(measurementType, value, position, context) {
+  _updateMeasurement(measurementType, value, _position, _context) {
     switch(measurementType) {
       case "quantity (tss)":
         this.C_TS = value;