1515318 - Parsing dd-MMM-yyyy date notation produces negative value

Status: RESOLVED DUPLICATE of bug 1439800

(Core :: JavaScript: Standard Library, defect, P3)

Description

[lholman]

Attachment: 2018-12-19 08_47_19.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36

Steps to reproduce:

Open Developer tools and navigate to the console. 
Create a new date variable using a date string in the format "dd-MMM-yyyy"
ex. var d = new Date('10-dec-2018')


Actual results:

The date returned is a negative value 
"Date -002018-12-10T04:56:02.000Z"



Expected results:

The date returned should not be a negative value.
ex. var d = new Date('10-dec 2018') 
Removing the hyphen from in-front of the year produces a positive value.

Comment 1

[Jason Orendorff [:jorendorff]]

Oh, wow, treating the '-' as a minus sign is ... surprising.

lholman, for what it's worth, there is a standard format for dates, which you can use:
https://tc39.github.io/ecma262/#sec-date-time-string-format

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

The severity field for this bug is relatively low, S3. However, the bug has 3 duplicates.
:sdetar, could you consider increasing the bug severity?

For more information, please visit auto_nag documentation.

Comment 6

[Thomas Wisniewski [:twisniewski]]

This is now causing a web-compat issue on JAL's flight booking page, as seen in bug 1825938. Maybe it's worth bumping up the priority here?

Comment 7

[Tooru Fujisawa [:arai]]

possible solution would be to check if the '-' immediately before the possible "year" follows another delimiter,
to distinguish new Date("10-dec-2018") and new Date("10-dec -2018").

Safari parses 10-dec-2018 as 2018-12-10 and 10-dec -2018 as -2018-12-10.