On Mar 1, 2009, at 10:28 AM, Allen Wirfs-Brock wrote:
From: Brendan Eich [mailto:[email protected]]
What should (new Function).name or (equivalently) Function().name
return? Precedent in some engines:
js> (new Function).name
anonymous
An anonymous function expression returns the empty string in some
implementations:
js> (function(){}).name
js> typeof (function(){}).name
string
js> (function(){}).name.length
0
I have a hard time buying (new Function).name === "anonymous" when
(function(){}).name==="". I think it is fine to have the name
distinguish functions created using new Function from functions
created via function expressions that don't have an explicit name.
However, the concept of "anonymous" could reasonably be applied to
either so using it for only one of them is likely to create
confusion for programmer to don't deeply understand this difference.
Plus, "anonymous" could actually be the declared name of a function.
In addition, at the Mt. View meeting we decide that if the target
function of a bind call has the empty string as its name then the
name of the function that is return from the bind is "bind anonymous
function". That would add to the confusion.
While it may go against precedent I think it would be more useful if
(new Function).name === "new Function". I can live with (function()
{}).name==="" although (function(){}).name==="anonymous function"
would probably be better.
Surprising though it may be, it seems that (new Function).name ===
"anonymous" may be relevant to Web compatibility. We changed
JavaScriptCore to match SpiderMonkey on this as a result of this bug:
http://bugzilla.opendarwin.org/show_bug.cgi?id=7726
While it's true that the code relying on the name may be completely
bogus, or that the specific string "anonymous" may only matter in the
Function.prototype.toString serialization and not in the name
property, I think the potential improvement is not great enough to be
worth the risk.
Note: this was not what I expected to find when I went spelunking in
our bug database; I thought we just blindly followed Gecko here before
I did the research.
I strongly suspect code also depends on (function(){}).name==="" but I
don't have a clear-cut example handy.
Regards,
Maciej
Regards,
Maciej
_______________________________________________
Es-discuss mailing list
[email protected]
https://mail.mozilla.org/listinfo/es-discuss
