Optional argument types

Andrea Giammarchi andrea.giammarchi at gmail.com
Wed Sep 26 05:06:59 PDT 2012

surely there's nothing to rush about, we survived already until now, no
reason to go for a quick solution and mine was just a proposal based on the
fact that most of the time contracts are based on primitives.

However, If the problem is typeof null then ES should fix that first but
AFAIK it came back to "object" at some point even under "use strict"
directive and I never understood why ...

primitives also means no wrappers allowed, which is a good practice,
generally speaking.

However, primitives does not mean "no Classes allowed" 'cause s:string and
s:String could be both valid, and different, one typeof, one instanceof, as
well as a:Array rather than just a:object where latter one would be
permissive while first one will look for instanceof Array.

The cross frame is nowadays a non-realworld-problem, I don't know any
application that uses direct frames access rather than postMessage or JSONP
... in both cases instanceof Array should simply work ... but of course as
long as it's possible to access other frames there could be a problem ...
in that case, the function that would like to accept Array from any other
window can specify a:object and do the [[Class]] check or use Array.isArray
to ensure the type after ... create cross frames problems for a type-hint
specification when the cross frame is disappeared from basically every
library is a non-sense, imho ... who wants to allow such security
problematic contract can use his own check, am I wrong?

As summary, string, number, boolean, undefined, function, null, object, as
allowed types would cover already many needed cases, adding Array, Object,
GenericScopedConstructor, global.name.spaced.Class on top of types can
cover 100% of cases I know.

Last but not least, if all this won't speed up a thing but actually will
decrease JS performances, as Alex pointed out at some point, I would vote
for **then don't** no matter what.

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