2014-03-09 21:05 GMT+01:00 Brendan Eich bren...@mozilla.com:
Tom has experimented, IIRC. I don't know which implementations preserve
extended property descriptor properties.
As Allen mentioned earlier, proxies should receive in their defineProperty
trap the full descriptor object as it was
Le 10/03/2014 08:02, Tom Van Cutsem a écrit :
Using Firefox's built-in direct proxies implementation I get a
TypeError. I'll investigate further and file a bug.
You already did https://bugzilla.mozilla.org/show_bug.cgi?id=601379 ;-)
David
___
Thanks Tom, I see what you mean but using proxies is a performance killer,
while I am trying to propose something that theoretically could also give a
performance boost.
I am not proposing custom descriptor attributes here, I am proposing
`type`, `arguments` (or `parameters`) and `returns` as
2014-03-10 11:10 GMT+01:00 David Bruant bruan...@gmail.com:
Using Firefox's built-in direct proxies implementation I get a TypeError.
I'll investigate further and file a bug.
You already did https://bugzilla.mozilla.org/show_bug.cgi?id=601379 ;-)
Thanks for refreshing my memory on that one
Note that ES6 proxies as specified permits
Object.defineProperty/getOwnPropertyDescriptor to pass custom attributes in
property descriptors and even passes them along (not sure if anybody has
actually implemented this yet) wherever there is a internal get descriptor/set
descriptor sequence.
my quick tests say no implementation does, all seem to create from the
scratch a new object with only known/described descriptor properties.
```javascript
Object.getOwnPropertyDescriptor(
Object.defineProperty(
{},'test',{value:123,type:'number'}
),
'test'
).type // undefined
```
I'd
Andrea Giammarchi wrote:
I'd love to know more about Tom experiments on this!
With his polyfill on the original proxy implementation, now that I think
about it.
https://github.com/tvcutsem/harmony-reflect
but originally
http://es-lab.googlecode.com/svn/trunk/src/proxies/DirectProxies.js
Uhm .. that looks just like Proxy and descriptors with known specd
properties ... might wait for Tom to know if he had anything to do with
types and custom properties in descriptors too.
Although my idea is more about types and less about proxies or descriptors
themselves, these are fine as they
Andrea Giammarchi wrote:
Although my idea is more about types
You are starting on the wrong foot there. Types mean something in CS.
Best if you start with use-cases instead of abusing the term. What code
do you want to write, and how exactly would it operate?
/be
As written before, and explained in the project, I can write descriptors
with optional extra properties such as:
**type**, describing as string the typeof, as Function the expected
instanceof, or as generic object as prototypeOf(expectedType)
```javascript
var o = {};
Object.defineProperty(o,
about the first example, I forgot the writable for the num property so
please read that as if I wrote:
```javascript
var o = {};
Object.defineProperty(o, 'num', {
writable: true,
value: 0,
type: 'number'
});
```
the library makes possible to create a partial shim of StructType in few
lines
last link is [the test file](
https://github.com/WebReflection/define-strict-properties/blob/master/test/define-strict-properties.js)
which better than examples in here describes what happens when the library
is around, how ES5 descriptors can guard properties and methods within
objects or
Yesterday, after my DHTMLConf talk, some developer asked me to
present/propose my idea about introducing **optional** types in an ES5
compatible way.
Here a quick overview of properties which aim is to guard types or methods
signatures, compatible with overloads for both number of arguments, and
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