mora-scripts/libs/lang/formatDate.js

Some collection scripts by myself

/**
 * @module      libs/lang/formatDate
 * @createdAt   2016-07-14
 *
 * @copyright   Copyright (c) 2016 Zhonglei Qiu
 * @license     Licensed under the MIT license.
 */

var MONTHS = [
  ['Jan', 'January'],
  ['Feb', 'February'],
  ['Mar', 'March'],
  ['Apr', 'April'],
  ['May', 'May'],
  ['Jun', 'June'],
  ['Jul', 'July'],
  ['Aug', 'August'],
  ['Sep', 'September'],
  ['Oct', 'October'],
  ['Nov', 'November'],
  ['Dec', 'December']
]
var WEEKS = [
  ['Sun', 'Sunday'],
  ['Mon', 'Monday'],
  ['Tue', 'Tuesday'],
  ['Wed', 'Wednesday'],
  ['Thu', 'Thursday'],
  ['Fri', 'Friday'],
  ['Sat', 'Saturday']
]

// 注意，要把长的放前面，表示优先匹配
var gre = /(?:yyyy|yy|mm|m|MM|M|dd|d|DD|Do|D|HH|H|hh|h|A|a|ii|i|ss|s|X|x)/g

/**
 * 格式化日期
 *
 * @param  {Date}   [date]  要格式化的日期，如果不传则使用当前日期
 * @param  {String} format  格式字符串，支持如下格式（以 2014-01-02 04:05:06 为例）：
 *
 *  FORMAT  |       EXAMPLE
 *  --------|----------------
 *  yyyy    |       2014
 *  yy      |       14
 *  m, mm   |       1, 01
 *  M, MM   |       Jan, January
 *  d, dd   |       2, 02
 *  D, DD   |       Thur, Thursday
 *  Do      |       2nd（Day of month with ordinal: 1st..31st）
 *  H, HH   |       4, 04（24 hour time)
 *  h, hh   |       4, 04 (12 hour time used with `a A`)
 *  a, A    |       am, AM
 *  i, ii   |       5, 05
 *  s, ss   |       6, 06
 *  x       |       1388646306
 *  X       |       1388646306346
 *
 * @return {String}         格式化后的日期
 *
 * @example
 *
 * formatDate('yyyy-mm-dd HH:ii:ss')
 * // 2016-07-08 15:03:02
 * formatDate(new Date(), 'h:ii A')
 * // 8:30 AM
 *
 * @author Zhonglei Qiu
 * @since 2.0.0
 */
module.exports = function(date, format) {
  if (!format) {
    format = date
    date = new Date()
  }

  var year = date.getFullYear()
  var month = date.getMonth()
  var day = date.getDate()
  var week = date.getDay()

  var hour = date.getHours()
  var minute = date.getMinutes()
  var second = date.getSeconds()

  var h = hour % 12
  var a = hour > 11 ? 'pm' : 'am'

  return format.replace(gre, function(key) {
    switch (key) {
      case 'yyyy': return year
      case 'yy': return year.toString().substr(2)
      case 'mm': return pad(month + 1)
      case 'm': return month + 1
      case 'MM': return MONTHS[month][1]
      case 'M': return MONTHS[month][0]
      case 'dd': return pad(day)
      case 'd': return day
      case 'DD': return WEEKS[week][1]
      case 'D': return WEEKS[week][0]
      case 'Do': return order(day)
      case 'HH': return pad(hour)
      case 'H': return hour
      case 'hh': return pad(h)
      case 'h': return h
      case 'a': return a
      case 'A': return a.toUpperCase()
      case 'ii': return pad(minute)
      case 'i': return minute
      case 'ss': return pad(second)
      case 's': return second
      case 'x': return Math.round(date.getTime() / 1000)
      case 'X': return date.getTime()
      /* istanbul ignore next 正则是精确匹配，不可能出现下面情况 */
      default: return key
    }
  })
}

function pad(num) {
  return num < 10 ? '0' + num : num
}

function order(day) {
  var prefix = day.toString()
  var suffix = 'th'
  var map = {'1': 'st', '2': 'nd', '3': 'rd'}

  if (day < 4 || day > 20) {
    suffix = map[prefix.toString().slice(-1)] || 'th'
  }

  return prefix + suffix
}