[wp-trac] [WordPress Trac] #38889: Proposition to allow an api.Value() using asynchronous callbacks

[WordPress Trac]

#38889: Proposition to allow an api.Value() using asynchronous callbacks
-------------------------------+------------------------------
 Reporter:  nikeo              |       Owner:
     Type:  enhancement        |      Status:  new
 Priority:  normal             |   Milestone:  Awaiting Review
Component:  Customize          |     Version:  trunk
 Severity:  normal             |  Resolution:
 Keywords:  reporter-feedback  |     Focuses:  javascript
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Comment (by nikeo):

 @westonruter thanks for examples and use case.

 If we continue with the same example of a section lazy loading its
 controls, my goal is to do things when the section controls are all
 embedded ( `fooSectionPopulated.done()` in your example ).

 The question to address is  : when is the section expansion actually done
 ?

 1. Is it when its value has been set ?
 2. Or is it when all its callback have finished their jobs ?


 If we consider that a section is expanded as soon as its value is set,
 then we might have issues using a code like this :

 {{{
 #!javascript
 section( section_id )(true);
 do_things_with_the_section_controls(); // <= some controls are not ready
 yet
 }}}



 If we consider that the section is completely expanded when all its
 callbacks are done, then it make sense to have a way to capture the
 callbacks promises and to use this syntax :
 {{{
 #!javascript
 section( section_id )(true).done( function() {
  do_things_with_the_section_controls(); //<= yes we are sure that all
 controls are ready because their promises are all resolved
 } );
 }}}



 Our approaches differ in the sense that the promise of the section ready (
 `fooSectionPopulated` ) is outside the callback, when I propose that the
 callback returns the promise.

 I agree that there are currently other ways to listen to the Value changes
 (bind / unbind ). I wanted to propose a complement to the code ( which has
 no impact if you don't specify the deferred param ), in order to allow
 different syntaxes when using `api.Value()` with asynchronous callbacks.

 Thanks for the discussion in any cases !

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Ticket URL: <https://core.trac.wordpress.org/ticket/38889#comment:5>
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