fix: adjust for substring logic

Author: el-yawd

src/csv2json.ts

@@ -310,7 +310,8 @@ export const Csv2Json = function(options: FullCsv2JsonOptions) {
             lastChar = fieldValue[lastIndex];
         // If the field starts and ends with a wrap delimiter
         if (firstChar === options.delimiter.wrap && lastChar === options.delimiter.wrap) {
-            return fieldValue.substring(1, lastIndex - 1);
+            // Handle the case where the field is just a pair of wrap delimiters 
+            return fieldValue.length <= 2 ? "" : fieldValue.substring(1, lastIndex);
         }
         return fieldValue;
     }