JavaScript get last day of Month – based on Year, Month and day

I need a JS function to get the last date of the month.
as an example, I need to get the last Wednesday of this month.

I will pass Year, Month and day as a arguments.

getLastDayOfMonth('2022', '02', 'Wednesday');

function getLastDayOfMonth(year, month, day){

     // Output should be like this

       2022-02-23    

    (this is last Wednesday of the month, according to the arguments- Year, month and Day)
}

>Solution :

Create a Date instance with the last day of the month then work backwards one day at a time until you match the day of the week you’re after

const dayIndex = {
  Sunday: 0,
  Monday: 1,
  Tuesday: 2,
  Wednesday: 3,
  Thursday: 4,
  Friday: 5,
  Saturday: 6
}

const getLastDayOfMonth = (year, month, dow) => {
  const day = dayIndex[dow]
  
  // init as last day of month
  const date = new Date(Date.UTC(parseFloat(year), parseFloat(month), 0))
  
  // work back one-day-at-a-time until we find the day of the week
  while (date.getDay() != day) {
    date.setDate(date.getDate() - 1)
  }
  
  return date
}

console.log(getLastDayOfMonth("2022", "02", "Wednesday"))

The numeric values are parsed as numbers so we don’t run into problems with zero-padded octal numbers.