WidgetToolbarRepository could warn user if it gets empty array of items

[ma2ciek]

Follow-up of ckeditor/ckeditor5-widget#54.

For now, it might happen that the user will make a typo in the config and without any error, the toolbar will be visible as empty.

This warning could be inside the WidgetToolbarRepository#register() or inside every toolbar (the second approach would be slightly better as it could have the more meaningful message, e.g. The "image.toolbar" config is undefined or an empty string. Please, make sure that your config doesn't contain a typo.

[ma2ciek]

Recently I've made such a mistake. I've created the following config:

{
	media: {
		toolbar: [ 'comment' ],
	}
}

and I was surprised that the comment button doesn't show up. Finally, I've found that I have a typo and it should be media -> mediaEmbed.

[ma2ciek]

And I remember that there was some idea in the past to consume the editor configuration (or maybe there wasn't?). That would be super useful to have an information like:

The `config.media` wasn't consumed by any plugin. Probably you miss some plugin or you have a typo in the editor's configuration.

But that would require at least some small changes in every plugin that uses editor's config.

WDYT @Reinmar @pjasiun?

[pjasiun]

The idea is very nice (I do not remember it was suggested before), but as you mentioned we should change plugins to do it...

Or not. We can check if config.get was called on all configuration options and log configuration that was not get.

[ma2ciek]

Right, we can check config.get calls. But probably it would solve the problem only for one level deep since many plugins get their configuration namespace.

[ma2ciek]

I'll extract the idea to the ticket in the CKE5 since I think it could be quite nice and low costing.

[pjasiun]

👍 But I think we should handle it in the next iteration when we will introduce debug mode.

[Reinmar]

I'm closing this because widget toolbar should not warn an error. Instead, it should make sure to not show the toolbar at all if it's empty. Why? Because a developer who's integrating CKEditor 5 with his app may want to hide some toolbar and then he/she should be able to configure it to null or whatever falsy value.

Passing a non-predefine (registered) config property to Editor.create() is a different story and #1266 covers it perfectly.