RocketChat/Rocket.Chat

import type { ISubscription } from '@rocket.chat/core-typings';
import { manageFavicon } from '@rocket.chat/favicon';
import { Meteor } from 'meteor/meteor';
import { Session } from 'meteor/session';
import { Tracker } from 'meteor/tracker';

import { ChatSubscription, ChatRoom } from '../../app/models/client';
import { getUserPreference } from '../../app/utils/client';
import { fireGlobalEvent } from '../lib/utils/fireGlobalEvent';

const fetchSubscriptions = (): ISubscription[] =>
    ChatSubscription.find(
        {
            open: true,
            hideUnreadStatus: { $ne: true },
            archived: { $ne: true },
        },
        {
            fields: {
                unread: 1,
                alert: 1,
                rid: 1,
                t: 1,
                name: 1,
                ls: 1,
                unreadAlert: 1,
                fname: 1,
                prid: 1,
            },
        },
    ).fetch();

Meteor.startup(() => {
    Tracker.autorun(() => {
        const userUnreadAlert = getUserPreference(Meteor.userId(), 'unreadAlert');

        let unreadAlert: false | '•' = false;

        const unreadCount = fetchSubscriptions().reduce(
            (ret, subscription) =>
                Tracker.nonreactive(() => {
                    const room = ChatRoom.findOne({ _id: subscription.rid }, { fields: { usersCount: 1 } });
                    fireGlobalEvent('unread-changed-by-subscription', {
                        ...subscription,
                        usersCount: room?.usersCount,
                    });

                    if (subscription.alert || subscription.unread > 0) {
                        // Increment the total unread count.
                        if (subscription.alert === true && subscription.unreadAlert !== 'nothing') {
                            if (subscription.unreadAlert === 'all' || userUnreadAlert !== false) {
                                unreadAlert = '•';
                            }
                        }
                        return ret + subscription.unread;
                    }
                    return ret;
                }),
            0,
        );

        if (unreadCount > 0) {
            if (unreadCount > 999) {
                Session.set('unread', '999+');
            } else {
                Session.set('unread', unreadCount);
            }
        } else if (unreadAlert !== false) {
            Session.set('unread', unreadAlert);
        } else {
            Session.set('unread', '');
        }
    });
});

Meteor.startup(() => {
    const updateFavicon = manageFavicon();

    Tracker.autorun(() => {
        const unread = Session.get('unread');
        fireGlobalEvent('unread-changed', unread);

        updateFavicon(unread);
    });
});