Felix Böhm wrote:
Hi guys,
just a first try for a proposal: Array.prototype.[filter/some/every]
currently require a function as an argument. Most of the time,
everything I want to do is check if they match a certain pattern. So
what I end up writing is a RegExp that matches the pattern, and
calling its test() method for every member of the array.
My proposal is to allow people to use a regular expression as an
argument for the three methods. Current implementations throw an error
when they don't get a function as an argument, so this won't break any
(working) code.
An example:
["fOo","bAr"].filter(function(elem){ return /foo/i.test(elem); });
should be replaceable with
["fOo","bAr"].filter(/foo/i);
Firefox 3 era js shell:
js> ["fOo","bAr"].filter(/foo/i);
fOo
js> version()
180
However, the latest Firefox and js shells do not make RegExp instances
callable:
js> ["fOo","bAr"].filter(/foo/i);
typein:5: TypeError: /foo/i is not a function
js> ["fOo","bAr"].filter(re=/foo/i, re.test.bind(re));
typein:6: TypeError: re is not a function
js> ["fOo","bAr"].filter(function(){return /foo/i});
["fOo", "bAr"]
We removed callable regexps because they violate ES3, as David-Sarah
Hopwood pointed out
(https://mail.mozilla.org/pipermail/es-discuss/2008-November/008008.html
and related).
For non-string members of the array, the current behavior of the
RegExp.prototype.test method (ie. converting the value to a string)
applies.
Any reasons why this is a bad idea? (Or is it just my bad attitude? :D )
typeof nativeObject == "function" <=> nativeObject is callable
is violated by making regexps callable.
/be
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