Excel value exported as undefined for non existing key only if cellstyle is associated for column specification

[joyblanks]

Consider the following snippet to replicate the issue:

Environment NodeJS v13 +

import excelExport from 'node-excel-export';

const specification = {
  col1: {displayName: 'COL1',  cellStyle: { fill: { fgColor: { rgb: 'FF57b370' } } } },
  col2: {displayName: 'COL2'},
};
const data = [
  {col1: 'some data1', col2: 'some data2'},
  {col1: 'some data1'},
  {col2: 'some data2'},
  {},
  {col1: undefined, col2: undefined}
];
excelExport.buildExport([{ name: 'Report', specification, data }]);

Current Output (ISSUE): In the excel it exports undefined as text for col1 where col1 value is not there or a non existent key/value property is not there or value is undefined, but works fine for col2 since it has no cellStyle associated.

COL1	COL2
some data1	some data2
some data1
undefined	some data2
undefined
undefined

Expected Output: If cell is undefined or not present as key, should export empty cell irrespective of styles added

COL1	COL2
some data1	some data2
some data1
	some data2

---

As a workaround for now I am using cellFormat to manually reset the value where cellstyle is applicable

const specification = {
  col1: {displayName: 'COL1',  cellStyle: { fill: { fgColor: { rgb: 'FF57b370' } } }, cellFormat: (v,r) => v===undefined?'':v },
  col2: {displayName: 'COL2'},
};