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Re: [FileAPI] File.slice spec bug

From: Jonas Sicking <jonas@sicking.cc>
Date: Tue, 12 Apr 2011 19:03:39 -0700
Message-ID: <BANLkTimSGUnPXzD_Qo9=uf5w-YrSoxdYCA@mail.gmail.com>
To: Dmitry Titov <dimich@chromium.org>
Cc: Darin Fisher <darin@chromium.org>, Mike Taylor <miketaylr@gmail.com>, Kyle Huey <me@kylehuey.com>, Jian Li <jianli@chromium.org>, "arun@mozilla.com" <arun@mozilla.com>, Maciej Stachowiak <mjs@apple.com>, Web Applications Working Group WG <public-webapps@w3.org>, Eric Uhrhane <ericu@google.com>
I just realized that string.slice also follows the pattern of Array.slice.

I really think we need to fix this to not cause a very unfortunate
inconsistency. I'd rather take some short term pain rather than foist
this upon developers forever. We're also all guilty of releasing
unprefixed code for a spec that isn't even in last call yet.

That leaves us with the two choices of removing File.slice or fixing it.

/ Jonas

On Tue, Apr 12, 2011 at 6:16 PM, Dmitry Titov <dimich@chromium.org> wrote:
> It can be more then it looks though - if site detects File.slice and then
> uses it, it will automatically pick up FF and Opera now because the method
> now is defined. But the code is assuming the 'length' semantics of the
> second parameter. So if the site is using recommended method of detection,
> the fact that it is only Chrome that implemented it so far does not
> necessarily reduce the scope of compat issue.
> For example, there is an open-source JS library that uses
> file.slice: http://www.plupload.com/index.php. They detect it by checking
> File.prototype.slice. So essentially, they are cross-browser.
> File.slice is probably going to be used by minority of advanced web
> developers (for offline apps or async upload kind of scenarios) and those
> care less about similarity with string.slice() perhaps. They routinely fight
> the subtle differences between browsers though. They already do detection
> for slice(), if FF will implement some newSlice(begin, end) - they probably
> will just add another line to detection, a piece of different math and curse
> the browser developers :-)
>
> On Tue, Apr 12, 2011 at 4:55 PM, Jonas Sicking <jonas@sicking.cc> wrote:
>>
>> On Tue, Apr 12, 2011 at 4:25 PM, Darin Fisher <darin@chromium.org> wrote:
>> > On Tue, Apr 12, 2011 at 4:02 PM, Mike Taylor <miketaylr@gmail.com>
>> > wrote:
>> >>
>> >> On 4/12/11 2:05 PM, Jonas Sicking wrote:
>> >>>
>> >>> It appears that Opera too implements File.slice. Would be great to
>> >>> know for how long it's been implemented.
>> >>
>> >> The first public build [1] with File.slice was made available last
>> >> week.
>> >> It's only been officially supported as of today, however, with the
>> >> release
>> >> of 11.10.
>> >>
>> >> [1]
>> >> http://my.opera.com/desktopteam/blog/2011/04/05/stability-gmail-socks
>> >>
>> >> - Mike
>> >
>> >
>> > As Jian mentioned earlier, File.slice has been available in Chrome since
>> > version 6, which was released Sept 2, 2010:
>> >
>> > http://googlechromereleases.blogspot.com/2010/09/stable-and-beta-channel-updates.html
>> > It seems like too much time has passed with this feature baked into
>> > Chrome
>> > for us to be able to change its behavior now.  While I agree that it
>> > would
>> > be nice for ".slice(...)" to work the same way in all contexts, I'm just
>> > not
>> > sure that this is something we can remove from Chrome at this point or
>> > even
>> > change.
>> > I'm very concerned about breaking existing web content.
>> > A new name for this function might be nice, but once you do that then
>> > I'm
>> > not sure that its arguments should really be any different than the
>> > current
>> > arguments for Blob.slice().  What's wrong with "start" and "length"
>> > other
>> > than that the fact that it differs from the parameters to Array.slice?
>> >  Why
>> > should Blob.createSubBlob favor the argument style of Array.slice over
>> > Blob.slice?
>>
>> I don't really care much about which style a new function would take.
>> I just think it's a really bad idea to have File.slice and Array.slice
>> which basically do exactly the same thing but take subtly different
>> arguments.
>>
>> > I guess I'm leaning toward no change at all and just taking our lumps
>> > for
>> > having created an inconsistent API :-/
>>
>> Given that only chrome has supported File.slice up until last week, I
>> doubt there are that many sites that rely on it. Do you know of any?
>> Any non-google ones (and thus would be harder to update)?
>>
>> / Jonas
>
>
Received on Wednesday, 13 April 2011 02:04:36 GMT

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