The `action` passed to jQuery.ajax is possibly `null`

[ixkaito]

When I add widgets from the Customizer, the console displays a TypeError action is null. Need to check if action and action.data exist.

[noisysocks]

Why is data null? Perhaps @wordpress/customize-widgets is doing something wrong cc. @kevin940726.

[ixkaito]

@noisysocks I'm not sure data is possibly null. Just to be safe.

[zieladam]

It seems like action is explicitly set to null here:

​https://github.com/WordPress/wordpress-develop/blob/master/src/js/_enqueues/wp/customize/selective-refresh.js#L773-L776

That code hasn't changed for last 5 years so it sounds like we're just triggering an unhappy path introduced in this commit:

​https://github.com/WordPress/wordpress-develop/commit/39ecd7846d24f5dd46833b68c6cb90dcdc070398

Given that context, Kai's fix looks good to me.

[desrosj]

Thanks all! Just for cross-referencing in Trac, introduced in [51187].

[desrosj]

In 51238:

Widgets: Avoid a TypeError when adding a widget in the Customizer.

This fixes a bug where action is set to null when adding a widget in the Customizer.

Fixes #53488. See #53421, #53419.

[desrosj]

Just realized I forgot to include props on the commit here. My apologies!

I just double checked, and everyone on the ticket has already received props for the 5.8 release, so you'll all be included in the release credits.