Fix required fields check on Bulk registration CSV upload, fixes #29 (#32)

src/components/ImportFeature.tsx

@@ -121,7 +121,11 @@ const FilePicker = () => {
 
   const verifyCsv = ({ data, meta, errors }: ParseResult<ImportLine>, { setValues, setStats, setError }) => {
     /* First, verify the presence of required fields */
-    const missingFields = expectedFields.filter(eF => meta.fields?.find(mF => eF === mF));
+    const missingFields = expectedFields.filter(eF => {
+      const result = meta.fields?.find(mF => eF === mF);
+      if (result === undefined) { return eF; } // missing field
+      return undefined; // field found
+    });
 
     if (missingFields.length > 0) {
       setError(translate("import_users.error.required_field", { field: missingFields[0] }));