const csvDataFormatted = csvData.map(item => {
        return cols.reduce((acc, col) => {
          const value = item[col.key];
           if (dateFields.includes(col.key)) {
            const date = new Date(value);
            acc[col.key] = isNaN(date.getTime()) ? value : format(date, 'dd-MM-yyyy');
          } 
          else {
            acc[col.key] = value;
          }
          return acc;
        }, {});
      });
      const csv = Papa.unparse([
        cols.map(col => col.header),
        ...csvDataFormatted.map(item => cols.map(col => item[col.key]))
      ]);

When exporting the csv file the value of schoolID was 2.60724E+18 instead of 2607241007009180000.

What I did is add this condition

if (col.key === 'schoolID') {
            acc[col.key] = value ? `'${value}` : '';
          }

but the single quote shouldn’t be included.