Get First Date and Last date of previous Month using javascript

Getting First date of previous Month:

 let GetFirstDateOfPreviousMonth=function(refDate){

let FirstDayPrevMonth = new Date(refDate.getFullYear(), refDate.getMonth()-1, 1);

return FirstDayPrevMonth;

}

Getting Last date of previous Month:

let GetLastDateOfPreviousMonth=function(refDate){

let LastDayPrevMonth = new Date(refDate.getFullYear(), refDate.getMonth(), 0);

return LastDayPrevMonth ;

}