1  'use strict'
  2  
  3  var DATE_TIME = /(\d{1,})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})(\.\d{1,})?.*?( BC)?$/
  4  var DATE = /^(\d{1,})-(\d{2})-(\d{2})( BC)?$/
  5  var TIME_ZONE = /([Z+-])(\d{2})?:?(\d{2})?:?(\d{2})?/
  6  var INFINITY = /^-?infinity$/
  7  
  8  module.exports = function parseDate (isoDate) {
  9    if (INFINITY.test(isoDate)) {
 10      // Capitalize to Infinity before passing to Number
 11      return Number(isoDate.replace('i', 'I'))
 12    }
 13    var matches = DATE_TIME.exec(isoDate)
 14  
 15    if (!matches) {
 16      // Force YYYY-MM-DD dates to be parsed as local time
 17      return getDate(isoDate) || null
 18    }
 19  
 20    var isBC = !!matches[8]
 21    var year = parseInt(matches[1], 10)
 22    if (isBC) {
 23      year = bcYearToNegativeYear(year)
 24    }
 25  
 26    var month = parseInt(matches[2], 10) - 1
 27    var day = matches[3]
 28    var hour = parseInt(matches[4], 10)
 29    var minute = parseInt(matches[5], 10)
 30    var second = parseInt(matches[6], 10)
 31  
 32    var ms = matches[7]
 33    ms = ms ? 1000 * parseFloat(ms) : 0
 34  
 35    var date
 36    var offset = timeZoneOffset(isoDate)
 37    if (offset != null) {
 38      date = new Date(Date.UTC(year, month, day, hour, minute, second, ms))
 39  
 40      // Account for years from 0 to 99 being interpreted as 1900-1999
 41      // by Date.UTC / the multi-argument form of the Date constructor
 42      if (is0To99(year)) {
 43        date.setUTCFullYear(year)
 44      }
 45  
 46      if (offset !== 0) {
 47        date.setTime(date.getTime() - offset)
 48      }
 49    } else {
 50      date = new Date(year, month, day, hour, minute, second, ms)
 51  
 52      if (is0To99(year)) {
 53        date.setFullYear(year)
 54      }
 55    }
 56  
 57    return date
 58  }
 59  
 60  function getDate (isoDate) {
 61    var matches = DATE.exec(isoDate)
 62    if (!matches) {
 63      return
 64    }
 65  
 66    var year = parseInt(matches[1], 10)
 67    var isBC = !!matches[4]
 68    if (isBC) {
 69      year = bcYearToNegativeYear(year)
 70    }
 71  
 72    var month = parseInt(matches[2], 10) - 1
 73    var day = matches[3]
 74    // YYYY-MM-DD will be parsed as local time
 75    var date = new Date(year, month, day)
 76  
 77    if (is0To99(year)) {
 78      date.setFullYear(year)
 79    }
 80  
 81    return date
 82  }
 83  
 84  // match timezones:
 85  // Z (UTC)
 86  // -05
 87  // +06:30
 88  function timeZoneOffset (isoDate) {
 89    if (isoDate.endsWith('+00')) {
 90      return 0
 91    }
 92  
 93    var zone = TIME_ZONE.exec(isoDate.split(' ')[1])
 94    if (!zone) return
 95    var type = zone[1]
 96  
 97    if (type === 'Z') {
 98      return 0
 99    }
100    var sign = type === '-' ? -1 : 1
101    var offset = parseInt(zone[2], 10) * 3600 +
102      parseInt(zone[3] || 0, 10) * 60 +
103      parseInt(zone[4] || 0, 10)
104  
105    return offset * sign * 1000
106  }
107  
108  function bcYearToNegativeYear (year) {
109    // Account for numerical difference between representations of BC years
110    // See: https://github.com/bendrucker/postgres-date/issues/5
111    return -(year - 1)
112  }
113  
114  function is0To99 (num) {
115    return num >= 0 && num < 100
116  }