[feature] .isInitialized() instead of making developers figure out that they must use internal .el variable? #2407

Is your feature request related to a problem? Please describe.
I found it unclear how to tell whether my object is initialized or not and only recently found that checking whether the object has mySortableObject?.el works, as opposed only checking if mySortableObject exists.

Describe the solution you'd like
Maybe some named helper function with a name like .isInitialized() or isUsingSortable()?

Describe alternatives you've considered
Otherwise it might be helpful to document that doing mySortableObject?.el is a better check than only mySortableObject (besides it being reported in this issue itself).

Additional context

let mySortableObject = null;
/* ... */
if (isUsingSortable()) {
  mySortableObject.destroy();
} else {
  mySortableObject = new Sortable(element, options);
}

function isUsingSortable() {
  return mySortableObject?.el;
}