Bug 32358 – Date object generates error for DD/MM/YYYY dates

• Component: JavaScriptCore
• Status: RESOLVED INVALID

[Estêvão Samuel Procópio Amaral]

When creating a date object with new Date("27/12/2009") (DD/MM/YYYY) an error is thrown saying it's an invalid date. JavaScriptCore expects dates in MM/DD/YYYY format and isn't able to parse DD/MM/YYYY dates.

[Estêvão Samuel Procópio Amaral]

Created attachment 44588 [details]
Patch to make JavaScriptCore parse DD/MM/YYYY dates correctly

[WebKit Review Bot]

style-queue ran check-webkit-style on attachment 44588 [details] without any errors.

[Oliver Hunt]

Comment on attachment 44588 [details]
Patch to make JavaScriptCore parse DD/MM/YYYY dates correctly

You need to include a testcase for this and i am concerned that will produce incorrect behaviour for
new Date("10/11/2009")
for instance

R- for the absence of tests (although i am concerned about the behaviour i'll wait on a testcase first)

[Alexey Proskuryakov]

Looking at ECMA-262, I don't see why either should be supported - per 15.9.1.15, the date-only format is YYYY-MM-DD.

Does this work in any other browser?

[Sam Weinig]

What does the spec say about this?  What do other browsers do?  Is this fixing a bug in a real site?

[Estêvão Samuel Procópio Amaral]

I came back to give me a R- and point the same issue that comment #3 did. I'm also concerned about dates with days and months in the same, month-valid range. I'll write some test cases and check it out, but no idea about how to identify, in this cases, if the date is in MM/DD/YYYY or DD/MM/YYYY. Shouldn't this parser be using information about the locale of the running system?

About comment #4, well, this date format is used in many countries, including here in Brazil (see http://en.wikipedia.org/wiki/Calendar_date#dd.2Fmm.2Fyyyy.2C_dd.mm.yyyy.2C_or_dd-mm-yyyy_.28day.2C_month.2C_year.29 for a list).

And about comment #5, yes. It's for fixing a real issue. I run through this issue yesterday trying to set the date I used in the example in a web app we're developping. This form demonstrates the problem, if you want to take a look: http://void.ufvjm.edu.br/woa2/index.php/date. The validation, which uses new Date(value), says the date is invalid although it's a real date in my location.

[rahul abrol]

Created attachment 44848 [details]
patch to handle dd/mm/yyyy format

this seems to work, if someone wants to write the testcase for it.  it assumes mm/dd/yyyy format unless 12 < month < 32, in which case it assumes dd/mm/yyyy.

this is how opera handles it.  firefox 3.5 just adds on the extra months, so 27/12/2009 is parsed as dec 12 2009 + 15 months = mar 12 2011.

[Karl Dubost]

`new Date("27/12/2009")` will generate `Invalid Date` in any browsers

```
Safari Technology Preview  208           20621.1.5.1
Firefox Nightly            135.0a1       13524.11.25
Google Chrome Canary       133.0.6871.0  6871.0
```

[Karl Dubost]

In https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-date-constructor

Else if numberOfArgs = 1, then

> …
>       ii. If v is a String, then
>           1. Assert: The next step never returns an abrupt completion because v is a String.
>           2. Let tv be the result of parsing v as a date, in exactly the same manner as for the parse method (21.4.3.2).

Which leads to https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-date.parse

With formats
https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-date-time-string-format


new Date("27/12/2009")
Invalid Date
new Date("2009/12/27")
Sun Dec 27 2009 00:00:00 GMT+0900 (Japan Standard Time)
new Date("2009-12-27")
Sun Dec 27 2009 09:00:00 GMT+0900 (Japan Standard Time)
new Date("27-12-2009")
Invalid Date
new Date("27/12/2009")
Invalid Date

Browsers are interoperable on this.