Promises

David Bruant bruant.d at gmail.com
Tue Nov 6 11:43:27 PST 2012


Le 06/11/2012 20:35, Rick Waldron a écrit :
> Based on a read through of 
> https://github.com/promises-aplus/promises-spec, these things 
> initially come to mind, please regard as a loose collection of varying 
> thoughts that may or may not be completely relevant:
>
> 1. The definition of a "promise" is really just a plain object or 
> function with an expando property, I would think that a language level 
> addition would require its own standard built-in object: Promise, 
> which when invoked as a constructor initializes a new promise object 
> which has a "then" method... Domenic has it covered from there.
I fully agree.

> 2. The notes describe some excellent practical implementation points, 
> but none of them are actually part of the ECMAScript standard, eg. 
> setTimeout, process.nextTick. Should these be specified or left 
> unspecified? Object.observe describes delivery as "Schedule change 
> events to be delivered asynchronously 'at the end of the turn'", which 
> is not very specific.
As I suggested, Object.observe opens the breach and I think it means the 
event loop (including the notion of "turn") will have to be fully 
specified within ECMAScript.

> 3. Does this belong in the language or would it make more sense to 
> exist as a "standard module"?
Are you referring to the event loop or promises?
event loop : the language
promises : arguably standard module

David


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