Updated distance in measurement helper so its a settable compoment. See example.js file in measurement helper folder

src/measurements/Measurement.js

@@ -2,11 +2,12 @@
 const convertModule = require('../convert/index');
 
 class Measurement {
-  constructor(type, variant, position, windowSize) {
+  constructor(type, variant, position, windowSize, distance = null) {
     this.type = type;               // e.g. 'pressure', 'flow', etc.
     this.variant = variant;         // e.g. 'predicted' or 'measured', etc..
     this.position = position;       // Downstream or upstream of parent object
     this.windowSize = windowSize;   // Rolling window size
+    this.distance = distance;       // Distance from parent, if applicable
 
     // Place all data inside an array
     this.values = [];               // Array to store all values
@@ -36,13 +37,12 @@ class Measurement {
     return this;
   }
 
+  setDistance(distance) {
+    this.distance = distance;
+    return this;
+  }
+
   setValue(value, timestamp = Date.now()) {
-    /*
-    if (value === undefined || value === null) {
-      value = null ;
-      //throw new Error('Value cannot be null or undefined');
-    }
-    */
 
     //shift the oldest value
     if(this.values.length >= this.windowSize){
@@ -168,7 +168,8 @@ class Measurement {
         this.type, 
         this.variant, 
         this.position,
-        this.windowSize
+        this.windowSize,
+        this.distance
       );
       
       // Copy values and timestamps