Context
Since menu type plugins are siblings in the DOMTree, it is not possible for menu type plugins to communicate with each other. Next to the menu type plugin, it is not possible to communicate from an editor type plugin to another editor type plugin or a menu type plugin.
| Info |
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Example use-case An end-user selects 2 IED's in 1 plug-in. In order to make a connection between IED's, the user want to open the selection in an another plug. |
Also, since Addons are not extending from a HTMLElement, Addons cannot subscribe to events on themselves.
HTML Events are only going up in the DOMTree, not down and/or to siblings.
Decision
# OpenSCD Core should make use of a central event-bus
Date: 2023-06-05
## Status
Open
...
If we want plugins for OpenSCD to be asynchronous accessible to each other, OpenSCD Core should make use of a central event-bus.
Instead of dispatching an event on the plugin itself, the plugin can dispatch an event on the central event-bus. HTML Events are only going up in the domtree, not down and/or to siblings.
We can solve this by creating a central event-bus that will be passed down to each plugin.This will take care of the current problems we're facing:
Addons
```ts
export class EventBus implements EventTarget {
...
removeEventListener(type: string, callback: EventListenerOrEventListenerObject): void {
if (this._eventListeners.has(type)) {
this._eventListeners.set(type, this._eventListeners.get(type)!.filter((cb) => cb !== callback));
}
}
}
```
## Decision
T.B.D.
...
Alternatives
Find a (seperate solution) for all problems mentioned.
Pro's:
Con's
Consequences
Implementing a central event-bus means that current OSCD plugins need some refactoring to dispatch events to the event-bus instead of dispatching events on itself.