On Tue, May 21, 2013 at 12:56 AM, Brendan Eich <[email protected]> wrote:
> Andrea Giammarchi wrote:
>
>> can I also suggest to analyze, if there's still any doubt left on a
>> method VS a property yet, this piece of code if not highlighted before?
>>
>
> I do not understand what you mean here.
>
>
I mean that JSON, as part of the specs, needs to consider that "magic"
property case, resulting into an `instanceof Object`, with an enumerable
property that will show up in a `for/in` loop but it's not able to mutate
the object.
```
var obj = JSON.parse('{"__proto__":[]}');
alert(obj instanceof Array); // false
alert(obj["__proto__"] instanceof Array); // true
obj["__proto__"] = obj["__proto__"];
// or
for (var key in obj) {
obj[key] = obj[key];
// could be a generic
// clone operation
}
alert(obj instanceof Array); // false
alert(obj instanceof Object); // true
```
Above kind of object is "not perfectly described in current specs" and is
different from any other where the `__proto__` is the inherited and not own
property.
This is what developers should be aware of, that `__proto__` might not be
what they think is while `Object.setPrototypeOf(obj, proto):obj` will
always work as expected, as well as `Object.getPrototypeOf(obj):proto`
All I am saying is that I understood reasons `__proto__` is there but I
hope there won't be any step backward about `Object.setPrototypeOf`
All the best and looking forward to read the notes.
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