Respond to "dialog:afterclose" once

Question

I'm trying to figure out how to respond to dialog:afterclose only once, and I'm not having any luck getting the syntax right (and I'm having trouble finding resources because most search results refer to jquery.once, which has been removed). Here's my best guess:

(function ($, Drupal) {
  Drupal.behaviors.MyCustomModule = {
    attach(context) {
      const $window = $(once('MyCustomModule', window, context));
      $window.on('dialog:afterclose', (e) => {
        console.log('closed');
      });
    }
  }
})(jQuery, Drupal);

That never fires. If I change $window to $(window) it fires, but eight times. Can anyone point me in the right direction? Thanks in advance.

Answer 1

Drupal behaviors are triggered once after DOMContentLoaded with document context, but AFAIK never in the window context. Also, in a global use-case like this, you do not want to limit your once-function with a context, because if your behavior is loaded later and not with the initial load, the document will never again be part of the context again and therefore will never match again.

So the solution should be simply changing your once element from window to document, without context:

(function ($, Drupal) {
  Drupal.behaviors.MyCustomModule = {
    attach(context) {
      const elements = once('MyCustomModule', document);
      elements.forEach( () => {
        $(window).doSomething();
      });
    }
  }
})(jQuery, Drupal);