*Fix circular reference error in CSV packing measurement

AppBuilder/platform/ABModel.js

@@ -102,6 +102,20 @@ module.exports = class ABModel extends ABModelCore {
             let lengthPacked = JSON.stringify(data).length;
             data = this.csvUnpack(data);
 
+            // Fix TypeError: Converting circular structure to JSON
+            const getCircularReplacer = () => {
+               const seen = new WeakSet();
+               return (key, value) => {
+                  if (typeof value === "object" && value !== null) {
+                     if (seen.has(value)) {
+                        return;
+                     }
+                     seen.add(value);
+                  }
+                  return value;
+               };
+            };
+
             // JOHNNY: getting "RangeError: Invalid string length"
             // when data.data is too large. So we are just going
             // to .stringify() the rows individually and count the
@@ -110,10 +124,16 @@ module.exports = class ABModel extends ABModelCore {
             let lengthUnpacked = 0;
             if (Array.isArray(data.data)) {
                for (var d = 0; d < data.data.length; d++) {
-                  lengthUnpacked += JSON.stringify(data.data[d]).length;
+                  lengthUnpacked += JSON.stringify(
+                     data.data[d],
+                     getCircularReplacer()
+                  ).length;
                }
             } else {
-               lengthUnpacked += JSON.stringify(data.data).length;
+               lengthUnpacked += JSON.stringify(
+                  data.data,
+                  getCircularReplacer()
+               ).length;
             }
 
             Object.keys(data)