JS: Date Constructor
Date()
-
Return a date string. Same as
(new Date()).toString()
new Date(…)
- Return a date object.
Date()
Date()
-
Return a string that represents the current time when this function is called. Sample return value:
"Tue May 22 2018 18:58:08 GMT-0700 (PDT)"
Arguments toDate()
are ignored.
console.log(Date()); // Sun Sep 06 2020 16:11:39 GMT-0700 (PDT)
Date() === (new Date()).toString()
// arg to Date() are ignored console.log(Date(1999) === Date());
new Date()
new Date()
- Return a date object that represents the current datetime when this function is called.
const d = new Date(); console.log(d.toString()); // Tue May 22 2018 18:58:08 GMT-0700 (PDT)
new Date(year, month …)
new Date(year, month)
- Return a date object of given (local) datetime.
new Date(year, month, day, hours, minutes, seconds, ms)
- The year, month are required, other parameters are optional.
The arguments are interpreted as local time. (If you want args to be UTC, use Date.UTC(…)
.
〔see Date.UTC〕
)
Argument format:
- year
- 4 digits integer.
- month
- 0 to 11. January is 0.
- day
- 1 to 31.
- hours
- 0 to 23.
- minutes
- 0 to 59.
- seconds
- 0 to 59.
- ms
- 0 to 999.
// note: January is 0 console.log((new Date(2016, 0, 1)).toUTCString()); // Fri, 01 Jan 2016 08:00:00 GMT
new Date(milliseconds)
new Date(milliseconds)
- Return a date object that represents the datetime of milliseconds since 01 January, 1970 UTC.
This milliseconds is how JavaScript represents datetime internally.
To get milliseconds from date object, use datetime.getTime()
.
const ms = 1428605303481; console.log( ms === (new Date(ms)).getTime(), ); // true
new Date(date_time_string)
new Date(DateTimeStr)
- Return a date object that represents the datetime in DateTimeStr.
Note:
new Date(DateTimeStr)
is equivalent to
new Date( Date.parse(DateTimeStr ) )
The Date.parse(DateTimeStr)
return milliseconds, then the
new Date(milliseconds)
turns that into a date instance.
console.log( (new Date("2016-04-08T15:48:22.000Z")).toString() === "Fri Apr 08 2016 08:48:22 GMT-0700 (PDT)", );
For the format of DateTimeStr, see Date.parse