datepicker/src/utils/date.js

import warnning from './warning'
import { weekMap } from '../const'

/**
 * 判断这一年是平年还是闰年
 * @param {String/Number} year 年份
 */
export const isLeapYear = year => (year % 4 === 0 && year % 100 !== 0) || (year % 400 === 0)

/**
 * 去掉字符串首尾空格
 * @param {String} str 字符串
 */
export const trimStr = str => str.replace(/^\s*/, '').replace(/\s*$/, '')

/**
 * 格式化月份或者天数
 * @param {String} dateStr 月份或者天数
 */
export const formatMonthOrDay = dateStr => {
  if ((`${dateStr}`).length === 2) {
    return dateStr
  }

  return `0${dateStr}`
}

/**
 * 获取当前年份
 */
export const getCurrentYear = () => new Date().getFullYear()

/**
 * 获取当前月份
 */
export const getCurrentMonth = () => formatMonthOrDay(new Date().getMonth() + 1)

/**
 * 获取当前天数
 */
export const getCurrentDay = () => formatMonthOrDay(new Date().getDate())

/**
 * 获取当前年份格式
 */
export const getCurrentDate = () => `${getCurrentYear()}-${getCurrentMonth()}-${getCurrentDay()}`

/**
 * 格式化日期
 * @param {String} date 日期
 */
export const formatDate = date => {
  const regexp = /(^(\d{4})(\s*[/\-\\:]\s*)(\d{1,2})(\s*[/\-\\:]\s*)(\d{1,2})$)|(^(\d{4})(\d{1,2})(\d{1,2})$)/
  const strArr = trimStr(date).match(regexp)

  if (!strArr) {
    return { format: '' }
  }

  const year = strArr[2] || strArr[8]
  let month = strArr[4] || strArr[9]
  let day = strArr[6] || strArr[10]

  if (+month > 12) {
    warnning('month exceed max month number 12')
    month = 12
  }

  if (+day > 31) {
    warnning('day exceed max day number 31')
    day = 31
  }

  month = formatMonthOrDay(month)
  day = formatMonthOrDay(day)

  return {
    format: `${year}-${month}-${day}`,
    year: year,
    month: month,
    day: day,
  }
}

/**
 * 具体日期适配器
 * @param {String} date 日期格式
 */
const specificDateAdapter = date => {
  const dateObj = formatDate(date)
  return flag => dateObj[flag]
}

/**
 * 获取指定日期的年份
 * @param {String} date 日期格式
 */
export const getYearFromSpecificDate = (date = getCurrentDate()) => specificDateAdapter(date)('year')

/**
 * 获取指定日期的月份
 * @param {String} date 日期格式
 */
export const getMonthFromSpecificDate = (date = getCurrentDate()) => specificDateAdapter(date)('month')

/**
 * 获取指定日期的天数
 * @param {String} date 日期格式
 */
export const getDayFromSepecificDate = (date = getCurrentDate()) => specificDateAdapter(date)('day')

/**
 * 获取指定日期的年份格式
 * @param {String} date 日期格式
 */
export const getDateFormatFromSepecificDate = (date = getCurrentDate()) => specificDateAdapter(date)('format')

/**
 * 获取指定月份的天数
 * @param {String} year 年份
 * @param {String} month 月份
 */
export const getDaysCountOfMonth = (month = getCurrentMonth(),
  year = getCurrentYear()) => new Date(year, month, 0).getDate()

/**
 * 获取一月中的第一天是星期几
 * @param {String} month 月份
 * @param {String} year 年份
 */
export const getWeekOfMonth = (month = getCurrentMonth(), year = getCurrentYear()) => (
  new Date(`${year}, ${month}, 01`).getDay()
)

/**
 * 获取一月中的第一天是星期几
 * @param {String} month 月份
 * @param {String} year 年份
 */
export const getWeekNameOfMonth = (month = getCurrentMonth(), year = getCurrentYear()) => {
  const dayNumber = getWeekOfMonth(month, year)
  return weekMap.get(dayNumber)
}

/**
 * 是否为当前天
 * @param {Sring/Number} year 年份
 * @param {Sring/Number} month 月份
 * @param {Sring/Number} day 天
 */
export const isCurrentDay = (year, month, day) => {
  const currentYear = getCurrentYear()
  const currentMonth = getCurrentMonth()
  const currentDay = getCurrentDay()
  /* eslint-disable eqeqeq */
  return (currentYear == year) && (currentMonth == month) && (currentDay == day)
}

/**
 * 判断日期是否合法
 * @param {String} date 日期
 */
export const isDateValid = date => {
  const regexp = /(^(\d{4})(\s*[/\-\\:]\s*)(\d{1,2})(\s*[/\-\\:]\s*)(\d{1,2})$)|(^(\d{4})(\d{1,2})(\d{1,2})$)/
  const strArr = trimStr(date).match(regexp)

  if (!strArr) {
    return false
  }

  const year = strArr[2] || strArr[8]
  const month = strArr[4] || strArr[9]
  const day = strArr[6] || strArr[10]

  if (+month > 12) {
    return false
  }

  const countOfMonth = getDaysCountOfMonth(month, year)
  if (+day > countOfMonth) {
    return false
  }

  return true
}