Get next date from weekday in JavaScript

Question

How can one return the next date of a given weekday (it could be either a number 0-6 or names Sunday-Saturday).

Example, if today, on Friday

Answer 1

To expand on user 190106's answer, this code should give you what you wanted:

function getNextDay(day, resetTime){
  var days = {
    sunday: 0, monday: 1, tuesday: 2,
    wednesday: 3, thursday: 4, friday: 5, saturday: 6
  };

  var dayIndex = days[day.toLowerCase()];
  if (dayIndex !== undefined) {
    throw new Error('"' + day + '" is not a valid input.');
  }

  var returnDate = new Date();
  var returnDay = returnDate.getDay();
  if (dayIndex !== returnDay) {
    returnDate.setDate(returnDate.getDate() + (dayIndex + (7 - returnDay)) % 7);
  }

  if (resetTime) {
    returnDate.setHours(0);
    returnDate.setMinutes(0);
    returnDate.setSeconds(0);
    returnDate.setMilliseconds(0);
  }
  return returnDate;
}

alert(getNextDay('thursday', true));