[v2] Node's constructor called from editor.registerNodeType

[yojeek]

Calling editor.registerNodeType(Node) will instantiate Node's class. I find this behaviour quite unexpected, especially because onDestroy method which I suppose must be used for cleanup of Node's dependencies wasn't called.

Is it really necessary to instantiate the class? Can't "category" and "title" be static properties?

public registerNodeType(type: AbstractNodeConstructor, options?: IRegisterNodeTypeOptions): void {
        if (this.events.beforeRegisterNodeType.emit({ type, options }).prevented) {
            return;
        }
        const nodeInstance = new type();
        this._nodeTypes.set(nodeInstance.type, {
            type,
            category: options?.category ?? "default",
            title: options?.title ?? nodeInstance.title,
        });
        this.events.registerNodeType.emit({ type, options });
    }

At least it should be documented because anything what is created inside constructor and not cleaned may potentially live forever (in my case it was websocket client polling for connections).

[newcat]

Unfortunately, abstract static properties are currently not supported in TypeScript (microsoft/TypeScript#34516). I could use static properties but this would not be enforced by the type system, so I opted for this approach instead. But I'll add some more documentation to emphasize the fact that the constructor is called during node registration.