Parses the value of the Date header in HTTP responses
npm install parsehttpdateParses the value of the Date header in HTTP responses.
Parses date-times from HTTP headers such as _Date_, _Last-Modified_, and _Expires_. An example of such a date-time is:
> Tue, 15 Nov 1994 08:12:31 GMT
The format [is defined by HTTP/1.1][http-1.1] (and [HTTP/1.0][http-1.0]) and is a subset of the specification used by the [Internet Message Format][imf].
Install parsehttpdate using npm or Yarn and import the function:
``javascript`
import parseHttpDate from 'parsehttpdate';
Alternatively, include parsehttpdate through unpkg:`html`
This alternative makes the function available at .
`javascript`
parseHttpDate('Wed, 21 Oct 2015 07:28:00 GMT');
This is how you can determine the time according to your server:
`javascript`
fetch('/')
.then(({ headers }) => headers.get('Date'))
.then(parseHttpDate)
.then(date => {
console.log(date.toTimeString());
});
This is the same example using an [async function][mdn-async-function]:
`javascript
async function getServerDate() {
const { headers } = await fetch('/');
return parseHttpDate(headers.get('Date'));
}
getServerDate()
.then(date => {
console.log(date.toTimeString());
});
`
If you are fairly certain the input is formatted correctly, you can squeeze out some extra performance by turning off validation.
`javascript`
parseHttpDate('Wed, 21 Oct 2015 07:28:00 GMT', false);
Does your date-time look nothing like the example above, but rather something like this?
> 1994-11-06T08:49:37Z
Congratulations: your date-time is formatted [according to ISO 8601][ecmascript-10-date-time]. _You don't need this library_. You don't need any library:
`javascript``
new Date('1994-11-06T08:49:37Z');
The HTTP/1.1 specification defines two obsolete formats besides the preferred format of the examples above:
> Sunday, 06-Nov-94 08:49:37 GMT
> Sun Nov 6 08:49:37 1994
This library does not support those; the supported format has been the preferred one since 1996. [Please create an issue][issues] if your use case requires the others.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
The Software is provided "as is", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement. in no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the Software or the use or other dealings in the Software.
[http-1.1]: https://tools.ietf.org/html/rfc7231#section-7.1.1.1
[http-1.0]: https://tools.ietf.org/html/rfc1945#section-3.3
[imf]: https://tools.ietf.org/html/rfc5322
[ecmascript-10-date-time]: http://www.ecma-international.org/ecma-262/10.0/#sec-date-time-string-format
[mdn-fetch]: https://developer.mozilla.org/docs/Web/API/Fetch_API
[mdn-async-function]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/async_function
[issues]: https://github.com/Pimm/parseHttpDate/issues