2015 02 03 → YYYY DD D about moment-parseformat

[johnnyNcsu]

I am also seeing this issue with date strings of form '09-15' -> DD-D; expected MM-DD (moment treats as MM-DD).

Similarly, inputs for '09' -> DD (moment treats as MM) and '12' -> D (moment treats as MM).

And 'March 28, 2001' -> MMMM D, YYYY (this may be technically ok but I would think a better result would be MMMM DD, YYYY).

[gr2m]

I don’t think that 09-15 or 09 would be useful input to be parsed with this library. I’d be okay to add proper parsing for YYYY M D / YYYY MM DD, although I have never seen this date format myself and given the issue is open for so long and nobody adding their +1s, it’s maybe too much of an edge case to be considered.

[johnnyNcsu]

@gr2m Thanks for the quick reply. I think I misunderstood the purpose of this library. I am looking for a library that exposes the internal momentjs format string used to interpret the input if it (momentjs) determines that input to be a valid date string (i.e. return a format string consistent with a valid momentjs date string - which can be more forgiving than strict ISO8601 strings). Do I understand correctly that this is not the intention of moment-parseformat?

[gr2m]

I am looking for a library that exposes the internal momentjs format string used to interpret the input if it (momentjs) determines that input to be a valid date string

I think momentjs is just passing the string to the native Date object that might or might not be able to parse the string correctly, it’s different based on the JavaScript runtime environment. I don’t think you can get access to the input format used to parse the string. This library is doing all the parsing by hand with lots and lots of regex :)

I use parseFormat to parse dates entered by humans. The idea is that someone can enter a date in a free text form and the app can understand both the entered date/time as well as the preferred date format of the user.

[johnnyNcsu]

I think momentjs is just passing the string to the native Date object that might or might not be able to parse the string correctly

@gr2m Thanks. Yes, this makes sense and likely explains why momentjs does not seem to expose parsed date fields - even though they appear to have some notion of this in their parse flags object (_pf.parsedDateParts). It seems to be an empty array every time I check it.

I will spend more time with momentjs to try too understand it a bit better. There do appear to be cases where momentjs is making some attempt to interpret date strings before calling Date on the string (e.g. a string of "2001" is interpreted as the year 2001 by momentjs but native Date will interpret this as 2001 milliseconds). Perhaps this is a feature request better placed with momentjs - although the opaqueness of the native Date object may impose significant challenges for fulfilling this request.

Thanks again!

[gr2m]

Keep me posted :) I’ll close this issue for the time being, maybe open a new issue if you have a plan™️