Messaging

Arc core provides a typed publish/subscribe messenger through @cratis/arc/messaging.

IMessenger

IMessenger publishes and subscribes by runtime type:

import { IMessenger } from '@cratis/arc/messaging';

class UserSelected {
    constructor(readonly userId: string) {
    }
}

messenger.subscribe(UserSelected, message => {
    console.log(message.userId);
});

messenger.publish(new UserSelected('42'));

Scoped hierarchy

Messenger can be created with a parent messenger:

import { Messenger } from '@cratis/arc/messaging';

const root = new Messenger();
const child = new Messenger(root);

Default behavior:

• Messages published in a child stay in that branch (no bubbling to parent).
• Messages published in a parent trickle down to all descendants recursively.

Override properties

Each messenger has two properties:

• bubbleToParent (default false) — bubble published messages to parent.
• trickleDownToChildren (default true) — forward messages to child messengers.