onChange event. Get an event when the content changes

Very nice plugin. Useful for many purposes.

Note that if you destroy the editor, then due to the 100ms delay, this callback gets called but there is no editor!

So I would recommend one of the following:
1. do nothing (maybe it doesn't matter if your callback crashes in this case) (but it seems to leave ckeditor in a buggy state, if your callback uses e.editor.getData() (this leads to an error))
2. in your callback function(e), check whether the editor still exists (I don't see how to do this, since e.editor does still exist and looks about the same) and deal with it as you like (this approach could lose the last 100ms of editing, probably not a problem if events are coming from a user's mouse and the system performance is fine, otherwise could be buggy)
3. postpone the destruction with an even longer timeout (easy, but relies on the system not being overloaded, and not very extendable to work with many plugins)
4. to destroy, trigger a change event before postponing the destruction (like 3) to ensure at least one final change will always fire before the destruction
5. modify this plugin (onchange) to modify the destruction mechanism to cancel pending callbacks and call the callback directly before proceeding with the destruction, perhaps with some clear signal that this is the final callback.

(3) and (4) assume you have control over all ways the editor might be destroyed, which in the general case (like in the presence of arbitrary other plugins) won't be true.

(5) would seem to be the best, but I don't know a good way to hook into the destruction.

-Matt

That's much easier than I imagined!

I agree that there's no need for onchange to notify about destruction, since (as you show) it's so easy to do it directly.

But I think that if the timer was going, then there was (probably) a change that the callback never heard about yet, so in this case the callback should be called one final time before the editor is destroyed, just to keep onchange's promise of notifying after any change.

This could come up if say a custom toolbar button does some final formatting and then closes the editor, in which case there would be no delay between the change and the destruction.

I made the changes shown below based on your fix, and it fixed the problem.

What the problem was: I have a toolbar button that closes the window, and for some reason (maybe afterCommandExec?) it triggers a change event. (Contrast this with the ajax.html sample page, which doesn't fire a change event when the "remove editor" button is pressed.) Then my change event callback contains:

                        console.log(e.editor.getData());

and this gets called when the "close editor" button is pressed, and this generates an error.

But with the following patch to onchange/plugin.js, the problem is fixed. There is still a change event when the button is pressed, but now getData() works correctly every time, so it's no problem.

      var timer = 0;
      // Avoid firing the event too often
      function somethingChanged()
      {
         if (timer || timer == null)
            return;
...
...
        // Kill the timer on editor destroy
        editor.on( 'destroy', function()
        {
            if ( timer )
                {
                    clearTimeout( timer );
                    editor.fire( 'change' );
                }
            timer = null;
        });

Thanks for the link to the other thread; I put an answer (and a pointer to this thread) there.
Destroying the editor is a supported action and it seems fairly easy to get a button to do it safely, as described in that thread. Whether it's "usual" or not probably depends very much on your application.
The more plugins that work well together, the better!