Futures

Anne van Kesteren annevk at annevk.nl
Fri Apr 26 11:51:00 PDT 2013


On Fri, Apr 26, 2013 at 7:44 PM, Juan Ignacio Dopazo
<dopazo.juan at gmail.com> wrote:
> I think Kevin's assertion is correct. According to the spec, callbacks are
> wrapped in something called a "future wrapper callback". When a promise is
> returned from the callback, the wrapper does this:
>
>> Let value be the result of invoking callback with argument as argument.
>> (...) run resolver's resolve with value and the synchronous flag set.
>
>
> resolve tries to adopt the promise by being recursive, effectively
> flattening the promise:
>>
>> If value is a JavaScript Object, set then to the result of calling the
>> JavaScript [[Get]] internal method of value with property name then.
>> If JavaScript IsCallable(then) is true [treats all thenables the same
>> way], run these substeps and then terminate these steps:
>> Call the JavaScript [[Call]] internal method of then with this value value
>> and resolve and reject as arguments.
>
> If resolved called the thenable's then() with accept and reject, it would
> only unwrap one layer.

Oops yeah. I guess that should be fixed. :/


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