Google appscript change timesheet to current month

index.js

const options = {
  weekday: 'short',
  year: 'numeric',
  month: '2-digit',
  day: 'numeric'
}

const getTotalDaysInMonth = (year, month = new Date().getMonth()) => {
  const _mnth = new Date(year, month, 0).getMonth() + 1
  const monthNumberArray = [_mnth - 1, _mnth, _mnth === 12 ? 1 : _mnth + 1]
  let arr = []
  for (let i = 0; i < monthNumberArray.length; i++) {
    arr.push({
      totalDays: new Date(year, monthNumberArray[i], 0).getDate(),
      month: monthNumberArray[i]
    })
  }
  return arr
}

const monthArray = [['January', 'Jan'],['February', 'Feb'],['March', 'Mar'],['April', 'Apr'],['May', 'May'],['June', 'Jun'],['July', 'Jul'],['August', 'Aug'],
['September', 'Sep'],['October', 'Oct'],['November', 'Nov'],['December', 'Dec']]
const dayInWeeks = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']

function onOpen(){
  const ui = SpreadsheetApp.getUi()
  ui.createMenu('Change month')
    .addItem('Change month now', 'changeSheetToMonthNow')
    .addToUi()
}

function changeSheetToMonthNow() {
  const ss = SpreadsheetApp.getActiveSheet()

  const date = new Date()
  const thisMonth = date.getMonth() + 1
  const thisYear = date.getFullYear()

  const getRowDate = ss.getSheetValues(4, 5, 5, 31)[0]
  const getRowDay = ss.getSheetValues(5, 5, 5, 31)[0]
  const getMonthString = ss.getSheetValues(2, 1, 1, 1)[0][0].split(' ')[5]

  // get string time sheet month
  const getCurrentMonthTimeSheet = monthArray.filter((x) => x[0] === getMonthString)[0]
  // get month of the current timesheet
  const getCurrentMonthTimeSheetNumber = monthArray.indexOf(monthArray.filter((x) => x[0] === getMonthString)[0]) + 1
  // get month now in string
  const getActualMonthNow = monthArray[thisMonth - 1]

  const getFirstDate = getRowDate[0]
  const getLastDate = getRowDate[getRowDate.length - 1]
  const getFirstDay = getRowDay[0]
  const getLastDay = getRowDay[getRowDay.length - 1]

  const getTotalDaysInThisMonth = getTotalDaysInMonth(thisYear, thisMonth)[1]
  const getTotalDaysIntCurrentTimeSheet = getTotalDaysInMonth(thisYear, getCurrentMonthTimeSheetNumber)[1]

  const dateOnThisMonth = []
  for (let i = parseInt(getLastDate) + 1; i <= getTotalDaysIntCurrentTimeSheet.totalDays; i++) {
    dateOnThisMonth.push({date: i, month: getTotalDaysIntCurrentTimeSheet.month})
  }
  for (let i = 1; i <= getTotalDaysInThisMonth.totalDays; i++) {
    dateOnThisMonth.push({date: i, month: getTotalDaysInThisMonth.month})
    if (dateOnThisMonth.length === getRowDate.length){
      break;
    }
  }
  for (let i = 0; i < dateOnThisMonth.length; i++) {
    const _getCurDate = new Date(thisYear, dateOnThisMonth[i].month - 1, dateOnThisMonth[i].date)
    const _day = dayInWeeks[_getCurDate.getDay()]
    dateOnThisMonth[i].day = _day
  }
  const dateValues = dateOnThisMonth.map((x) => x.day)
  let str = ``
  if (thisMonth !== 1) {
    str = `${dateOnThisMonth[0].date} ${monthArray[thisMonth - 2][0]} ${thisYear} to ${dateOnThisMonth[dateOnThisMonth.length - 1].date} ${monthArray[thisMonth - 1][0]} ${thisYear}`
  } else {
    str = `${dateOnThisMonth[0].date} ${monthArray[11][0]} ${thisYear} to ${dateOnThisMonth[dateOnThisMonth.length - 1].date} ${monthArray[12][0]} ${thisYear}`
  }

  // change all
  ss.getRange(5, 5, 1, getRowDate.length).setValues([dateValues])
  ss.getRange('A2:AP2').setValue(str)
  if (thisMonth !== 1) {
  SpreadsheetApp.getActiveSpreadsheet().rename(`Timesheet Timas - ${dateOnThisMonth[0].date} ${monthArray[thisMonth - 2][1]} ${thisYear} - ${dateOnThisMonth  [dateOnThisMonth.length - 1].date} ${monthArray[thisMonth - 1][1]} ${thisYear}_Imam Syafei`)
  } else {
    SpreadsheetApp.getActiveSpreadsheet().rename(`Timesheet Timas - ${dateOnThisMonth[0].date} ${monthArray[11][0]} ${thisYear} - ${dateOnThisMonth[dateOnThisMonth.length - 1].date} ${monthArray[12][0]} ${thisYear}_Imam Syafei`)
  }
}