ArrayDate

const startDate = "01-05-2020";
const endDate = "31-07-2020";

const getRangeMonth = (startDate, endDate) => {
  /* CONFIG VARIABLE */
  const monthNames = [
    "Jan",
    "Feb",
    "Mar",
    "Apr",
    "Mei",
    "Jun",
    "Jul",
    "Agu",
    "Sep",
    "Okt",
    "Nov",
    "Des",
  ];
  const startDateSplit = startDate.split("-");
  const endDateSplit = endDate.split("-");

  const startYear = Number(startDateSplit[2]);
  const endYear = Number(endDateSplit[2]);
  const startMonth = Number(startDateSplit[1]) - 1;
  const endMonth = Number(endDateSplit[1]) - 1;

  /* MAIN VARIABLE */
  let rangeMonthInAYear = [];
  let monthRange = [];
  let dateBar = [];

  /* CHECK IF IS LEAP YEAR */
  const leapYear = (year) => {
    if (Number(year) % 4 === 0) {
      if (Number(year) % 100 === 0) {
        if (Number(year) % 400 === 0) {
          return true;
        } else {
          return false;
        }
      } else {
        return true;
      }
    } else {
      return false;
    }
  };

  /* GENERATE DATE BAR */
  const generateDateBar = (dateStart, dateEnd, month, year) => {
    for (let i = dateStart; i <= dateEnd; i++) {
      const dateVar = `${i < 10 ? `0${i}` : i}/${
        month < 10 ? `0${month}` : month
      }/${year}`;
      dateBar.push(dateVar);
    }
  };

  /* COMPLICATED LOGIC */
  // Generate rangeMonthInAYear
  if (startYear === endYear) {
    rangeMonthInAYear.push(endMonth - startMonth);
  } else {
    for (let i = startYear; i <= endYear; i++) {
      if (startYear === i) {
        rangeMonthInAYear.push(11 - startMonth);
      } else if (endYear === i) {
        rangeMonthInAYear.push(0 + endMonth);
      } else {
        rangeMonthInAYear.push(11);
      }
    }
  }

  // Generate monthRange
  for (let i = 0; i < rangeMonthInAYear.length; i++) {
    for (let j = 0; j <= rangeMonthInAYear[i]; j++) {
      if (rangeMonthInAYear.length !== 1) {
        if (i === rangeMonthInAYear.length - 1) {
          monthRange.push(0 + j);
        } else {
          monthRange.push(11 - rangeMonthInAYear[i] + j);
        }
      } else {
        monthRange.push(startMonth + j);
      }
    }
  }

  // Generate Date
  let yearGenerateDate = startYear;
  for (let i = 0; i < monthRange.length; i++) {
    if (monthRange[i] === 0) yearGenerateDate++;

    if (monthRange[i] === 1) {
      if (leapYear(yearGenerateDate)) {
        generateDateBar(1, 29, monthRange[i] + 1, yearGenerateDate);
      } else {
        generateDateBar(1, 28, monthRange[i] + 1, yearGenerateDate);
      }
    } else {
      if (
        monthRange[i] === 0 ||
        monthRange[i] === 2 ||
        monthRange[i] === 4 ||
        monthRange[i] === 6 ||
        monthRange[i] === 7 ||
        monthRange[i] === 9 ||
        monthRange[i] === 11
      ) {
        generateDateBar(1, 31, monthRange[i] + 1, yearGenerateDate);
      } else {
        generateDateBar(1, 30, monthRange[i] + 1, yearGenerateDate);
      }
    }
  }

  // console.log(rangeMonthInAYear);
  // console.log(monthRange)

  return dateBar;
};

const result = getRangeMonth(startDate, endDate);
console.log(result);