javaScriptで日付比較をするとして、以下のように記述するとします。
if("2023/12/31" > "2013/12/15"){
～処理～
}
多くのブラウザでは正常に動作するそうですが一部のブラウザなどではエラーを吐いてしますのでそのようなブラウザでも正常に動作するようにするためには一度timeに直します。
PHPではstrtotimeという便利な関すうが用意されているのですがjavaScriptではそのようなものはありません。
調べてみたところそのような関数を作っている方がいらっしゃったので掲載させていただきます。
http://locutus.io/php/datetime/strtotime/
module.exports = function strtotime (text, now) {
// discuss at: http://locutus.io/php/strtotime/
// original by: Caio Ariede (http://caioariede.com)
// improved by: Kevin van Zonneveld (http://kvz.io)
// improved by: Caio Ariede (http://caioariede.com)
// improved by: A. Matías Quezada (http://amatiasq.com)
// improved by: preuter
// improved by: Brett Zamir (http://brett-zamir.me)
// improved by: Mirko Faber
// input by: David
// bugfixed by: Wagner B. Soares
// bugfixed by: Artur Tchernychev
// bugfixed by: Stephan Bösch-Plepelits (http://github.com/plepe)
// note 1: Examples all have a fixed timestamp to prevent
// note 1: tests to fail because of variable time(zones)
// example 1: strtotime('+1 day', 1129633200)
// returns 1: 1129719600
// example 2: strtotime('+1 week 2 days 4 hours 2 seconds', 1129633200)
// returns 2: 1130425202
// example 3: strtotime('last month', 1129633200)
// returns 3: 1127041200
// example 4: strtotime('2009-05-04 08:30:00 GMT')
// returns 4: 1241425800
// example 5: strtotime('2009-05-04 08:30:00+00')
// returns 5: 1241425800
// example 6: strtotime('2009-05-04 08:30:00+02:00')
// returns 6: 1241418600
// example 7: strtotime('2009-05-04T08:30:00Z')
// returns 7: 1241425800
var parsed
var match
var today
var year
var date
var days
var ranges
var len
var times
var regex
var i
var fail = false
if (!text) {
return fail
}
// Unecessary spaces
text = text.replace(/^\s+|\s+$/g, '')
.replace(/\s{2,}/g, ' ')
.replace(/[\t\r\n]/g, '')
.toLowerCase()
// in contrast to php, js Date.parse function interprets:
// dates given as yyyy-mm-dd as in timezone: UTC,
// dates with "." or "-" as MDY instead of DMY
// dates with two-digit years differently
// etc...etc...
// ...therefore we manually parse lots of common date formats
var pattern = new RegExp([
'^(\\d{1,4})',
'([\\-\\.\\/:])',
'(\\d{1,2})',
'([\\-\\.\\/:])',
'(\\d{1,4})',
'(?:\\s(\\d{1,2}):(\\d{2})?:?(\\d{2})?)?',
'(?:\\s([A-Z]+)?)?$'
].join(''))
match = text.match(pattern)
if (match && match[2] === match[4]) {
if (match[1] > 1901) {
switch (match[2]) {
case '-':
// YYYY-M-D
if (match[3] > 12 || match[5] > 31) {
return fail
}
return new Date(match[1], parseInt(match[3], 10) - 1, match[5],
match[6] || 0, match[7] || 0, match[8] || 0, match[9] || 0) / 1000
case '.':
// YYYY.M.D is not parsed by strtotime()
return fail
case '/':
// YYYY/M/D
if (match[3] > 12 || match[5] > 31) {
return fail
}
return new Date(match[1], parseInt(match[3], 10) - 1, match[5],
match[6] || 0, match[7] || 0, match[8] || 0, match[9] || 0) / 1000
}
} else if (match[5] > 1901) {
switch (match[2]) {
case '-':
// D-M-YYYY
if (match[3] > 12 || match[1] > 31) {
return fail
}
return new Date(match[5], parseInt(match[3], 10) - 1, match[1],
match[6] || 0, match[7] || 0, match[8] || 0, match[9] || 0) / 1000
case '.':
// D.M.YYYY
if (match[3] > 12 || match[1] > 31) {
return fail
}
return new Date(match[5], parseInt(match[3], 10) - 1, match[1],
match[6] || 0, match[7] || 0, match[8] || 0, match[9] || 0) / 1000
case '/':
// M/D/YYYY
if (match[1] > 12 || match[3] > 31) {
return fail
}
return new Date(match[5], parseInt(match[1], 10) - 1, match[3],
match[6] || 0, match[7] || 0, match[8] || 0, match[9] || 0) / 1000
}
} else {
switch (match[2]) {
case '-':
// YY-M-D
if (match[3] > 12 || match[5] > 31 || (match[1] < 70 && match[1] > 38)) {
return fail
}
year = match[1] >= 0 && match[1] <= 38 ? +match[1] + 2000 : match[1]
return new Date(year, parseInt(match[3], 10) - 1, match[5],
match[6] || 0, match[7] || 0, match[8] || 0, match[9] || 0) / 1000
case '.':
// D.M.YY or H.MM.SS
if (match[5] >= 70) {
// D.M.YY
if (match[3] > 12 || match[1] > 31) {
return fail
}
return new Date(match[5], parseInt(match[3], 10) - 1, match[1],
match[6] || 0, match[7] || 0, match[8] || 0, match[9] || 0) / 1000
}
if (match[5] < 60 && !match[6]) {
// H.MM.SS
if (match[1] > 23 || match[3] > 59) {
return fail
}
today = new Date()
return new Date(today.getFullYear(), today.getMonth(), today.getDate(),
match[1] || 0, match[3] || 0, match[5] || 0, match[9] || 0) / 1000
}
// invalid format, cannot be parsed
return fail
case '/':
// M/D/YY
if (match[1] > 12 || match[3] > 31 || (match[5] < 70 && match[5] > 38)) {
return fail
}
year = match[5] >= 0 && match[5] <= 38 ? +match[5] + 2000 : match[5]
return new Date(year, parseInt(match[1], 10) - 1, match[3],
match[6] || 0, match[7] || 0, match[8] || 0, match[9] || 0) / 1000
case ':':
// HH:MM:SS
if (match[1] > 23 || match[3] > 59 || match[5] > 59) {
return fail
}
today = new Date()
return new Date(today.getFullYear(), today.getMonth(), today.getDate(),
match[1] || 0, match[3] || 0, match[5] || 0) / 1000
}
}
}
// other formats and "now" should be parsed by Date.parse()
if (text === 'now') {
return now === null || isNaN(now)
? new Date().getTime() / 1000 | 0
: now | 0
}
if (!isNaN(parsed = Date.parse(text))) {
return parsed / 1000 | 0
}
// Browsers !== Chrome have problems parsing ISO 8601 date strings, as they do
// not accept lower case characters, space, or shortened time zones.
// Therefore, fix these problems and try again.
// Examples:
// 2015-04-15 20:33:59+02
// 2015-04-15 20:33:59z
// 2015-04-15t20:33:59+02:00
pattern = new RegExp([
'^([0-9]{4}-[0-9]{2}-[0-9]{2})',
'[ t]',
'([0-9]{2}:[0-9]{2}:[0-9]{2}(\\.[0-9]+)?)',
'([\\+-][0-9]{2}(:[0-9]{2})?|z)'
].join(''))
match = text.match(pattern)
if (match) {
// @todo: time zone information
if (match[4] === 'z') {
match[4] = 'Z'
} else if (match[4].match(/^([\+-][0-9]{2})$/)) {
match[4] = match[4] + ':00'
}
if (!isNaN(parsed = Date.parse(match[1] + 'T' + match[2] + match[4]))) {
return parsed / 1000 | 0
}
}
date = now ? new Date(now * 1000) : new Date()
days = {
'sun': 0,
'mon': 1,
'tue': 2,
'wed': 3,
'thu': 4,
'fri': 5,
'sat': 6
}
ranges = {
'yea': 'FullYear',
'mon': 'Month',
'day': 'Date',
'hou': 'Hours',
'min': 'Minutes',
'sec': 'Seconds'
}
function lastNext (type, range, modifier) {
var diff
var day = days[range]
if (typeof day !== 'undefined') {
diff = day - date.getDay()
if (diff === 0) {
diff = 7 * modifier
} else if (diff > 0 && type === 'last') {
diff -= 7
} else if (diff < 0 && type === 'next') {
diff += 7
}
date.setDate(date.getDate() + diff)
}
}
function process (val) {
// @todo: Reconcile this with regex using \s, taking into account
// browser issues with split and regexes
var splt = val.split(' ')
var type = splt[0]
var range = splt[1].substring(0, 3)
var typeIsNumber = /\d+/.test(type)
var ago = splt[2] === 'ago'
var num = (type === 'last' ? -1 : 1) * (ago ? -1 : 1)
if (typeIsNumber) {
num *= parseInt(type, 10)
}
if (ranges.hasOwnProperty(range) && !splt[1].match(/^mon(day|\.)?$/i)) {
return date['set' + ranges[range]](date['get' + ranges[range]]() + num)
}
if (range === 'wee') {
return date.setDate(date.getDate() + (num * 7))
}
if (type === 'next' || type === 'last') {
lastNext(type, range, num)
} else if (!typeIsNumber) {
return false
}
return true
}
times = '(years?|months?|weeks?|days?|hours?|minutes?|min|seconds?|sec' +
'|sunday|sun\\.?|monday|mon\\.?|tuesday|tue\\.?|wednesday|wed\\.?' +
'|thursday|thu\\.?|friday|fri\\.?|saturday|sat\\.?)'
regex = '([+-]?\\d+\\s' + times + '|' + '(last|next)\\s' + times + ')(\\sago)?'
match = text.match(new RegExp(regex, 'gi'))
if (!match) {
return fail
}
for (i = 0, len = match.length; i < len; i++) {
if (!process(match[i])) {
return fail
}
}
return (date.getTime() / 1000)
}
strtotime("1996/9/16");
のように記述するとtimeで出力してくれます。
