CODE EXAMPLE FOR JAVASCRIPT

javascript date add days

function addDays(originalDate, days){
  cloneDate = new Date(originalDate.valueOf());
  cloneDate.setDate(cloneDate.getDate() + days);
  return cloneDate;
}

let appointment = new Date("February 12, 2021 00:00:00");
let newAppointment = addDays(appointment, 7);

console.log(appointment.getDate()); // 12
console.log(newAppointment.getDate()); // 19