fix(gr-sheet): Add support for NONE for UoM references

packages/gr-sheet/src/index.ts

@@ -247,6 +247,13 @@ async function * generateGRItems(parsedSheetItems, opts) {
     throw new Error(`Unable to resolve reference, ${itemID}`);
   }
 
+  const resolveNullableReference = function (cellContents: string, mode: Predicate["mode"]): ReturnType<typeof resolveReference> | null {
+    if (/none/i.test(cellContents)) {
+      return null;
+    }
+    return resolveReference(cellContents, mode);
+  }
+
   const resolveRelated = function resolveRelated(cellContents: string) {
 
     //const itemID = sheetItemID.split(' ')[0];
@@ -655,7 +662,7 @@ const SupportedSheets = {
         remarks: item.remarks,
         orientation: item.orientation,
         abbreviation: item.abbreviation,
-        unitOfMeasurement: resolveReference(item.unitOfMeasurement, 'id'),
+        unitOfMeasurement: resolveNullableReference(item.unitOfMeasurement, 'id'),
       };
     },
   }),
@@ -747,7 +754,7 @@ const SupportedSheets = {
           ? ParameterType.FILE
           : ParameterType.MEASURE,
         unitOfMeasurement: type !== "Reference File"
-          ? resolveReference(unitOfMeasurement, 'id') as string | Predicate
+          ? resolveNullableReference(unitOfMeasurement, 'id') as string | Predicate | null
           : null,
         value: type === "Reference File"
           ? fileRef