[wp-trac] [WordPress Trac] #38728: Prevent previewer becoming frozen when refreshing too fast

[WordPress Trac]

#38728: Prevent previewer becoming frozen when refreshing too fast
--------------------------+--------------------
 Reporter:  nikeo         |       Owner:
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  4.7
Component:  Customize     |     Version:  trunk
 Severity:  normal        |  Resolution:
 Keywords:  needs-patch   |     Focuses:
--------------------------+--------------------
Changes (by westonruter):

 * keywords:  has-patch => needs-patch


Comment:

 @nikeo thanks for the patch and the detailed writeup. I agree that
 `refresh` returning a promise would be a good improvement, but that would
 fall in the realm of an enhancement so we'll have to target that for 4.8.

 As for the defect itself, I was able to reproduce it as well. I'm testing
 this by editing the `blogname` setting in Twenty Sixteen to disable the
 `postMessage` transport so that every change to the site title causes a
 refresh.

 Your idea to wait to do a refresh until the previous request has finished
 works but it doesn't take into account a key consideration. Consider
 WordPress running on a slow site where a refresh could take 10 seconds.
 With your patch, if I make a change, then wait a second, and then make a
 second change while the preview is being refreshed, the second change I
 made will fail to appear in the preview when it finishes loading. So it is
 important that whenever `refresh` is called that it `destroy` any existing
 request to load the preview and defer to a new `PreviewFrame`.

--
Ticket URL: <https://core.trac.wordpress.org/ticket/38728#comment:8>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform