Returns the year fraction representing the number of whole days between start_date and end_date.
| Name | Type | Description |
| arg1 | any | Is a serial date number that represents the start date. |
| arg2 | any | Is a serial date number that represents the end date. |
| arg3 | any | Is the type of day count basis to use. |
builder.CreateFile("xlsx");
const oWorksheet = Api.GetActiveSheet();
var oFunction = Api.GetWorksheetFunction();
var ans = oFunction.YEARFRAC("12/7/1981", "11/5/2018");
oWorksheet.GetRange("C1").SetValue(ans);
builder.SaveFile("xlsx", "YEARFRAC.xlsx");
builder.CloseFile();