Moment parse zone gives unexpected result

Question

const input = '02/02/1700 12:30'
const inputFormat = ['DD/MM/YYYY HH:mm']
const displayFormat = 'YYYY-MM-DDTHH:mm:ss'


console.log(moment(input, inputFormat, true))
console.log(moment(input, inputFormat, true).format())
console.log(moment.utc(input, inputFormat, true))
console.log(moment.utc(input, inputFormat, true).format())
console.log(moment.parseZone(input, inputFormat, true))
console.log(moment.parseZone(input, inputFormat, true).format())
console.log(moment.tz(input, inputFormat, true, 'Asia/Hong_Kong'))
console.log(moment.tz(input, inputFormat, true, 'Asia/Hong_Kong').format())

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.27.0/moment.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment-timezone/0.5.31/moment-timezone-with-data.min.js"></script>

https://jsfiddle.net/y9gtvbdn/

The above example the result of parseZone give 1700-02-02T12:29:18Z which is different from input '02/02/1700 12:30'. Anyone can explain this to me?

Hi. Please don't just link to external code. You can use an external site to *supplement* your question, but you need to include the specific code you are asking about in the question itself. Please read [*How do I ask a good question?*](https://stackoverflow.com/help/how-to-ask) and [*How to create a Minimal, Reproducible Example*](https://stackoverflow.com/help/how-to-ask) from the Stack Overflow help center. Thanks. (Also, there's too much in your fiddle anyway - limit your code to the specific question - remove the parts that aren't relevant.) — Matt Johnson-Pint, Jul 23 '20 at 17:21
Just want to show different cases. Anyway, I suspect this is a moment bug. — Morty Choi, Jul 24 '20 at 04:43

score 1 · Accepted Answer · answered Jul 24 '20 at 16:25

A few things:

Don't log a moment directly. Always use an output function like format
When you parse in Moment, internally Moment is calling setters on a Date object. Since you aren't passing seconds or milliseconds, the setter for that is never called. If you did have seconds, you'd see them set to zero as expected.
The reason that they aren't in this case is that there's a longstanding browser bug with Date objects constructed on or before 1883-11-18T12:03:57.999Z. See this comment, and the associated question. This isn't a moment bug, but a JavaScript browser quirk. This only matters for very early dates.
parseZone is specifically for use when the input has a time zone offset in it - either numeric like -07:00 or a Z (which indicates UTC). Your example input string has neither in it.

Moment parse zone gives unexpected result

1 Answers1