Method monthEnd

src/danfojs-base/core/daterange.ts:212–217

(startDate: Date, endDate: Date)

  }

  private monthEnd(startDate: Date, endDate: Date) {
    let endMonth = endDate.getMonth()
    let diffYear = endDate.getFullYear() - startDate.getFullYear()
    let endRange = (12 * diffYear) + endMonth
    return endRange
  }

  private monthRange(range: number[]): number[][] {
    let minus: number;