MemberCount: add thread support (#2785)

Co-authored-by: v <vendicated@riseup.net>

src/plugins/memberCount/MemberCount.tsx

@@ -5,9 +5,10 @@
  */
 
 import { getCurrentChannel } from "@utils/discord";
+import { isObjectEmpty } from "@utils/misc";
 import { SelectedChannelStore, Tooltip, useEffect, useStateFromStores } from "@webpack/common";
 
-import { ChannelMemberStore, cl, GuildMemberCountStore, numberFormat } from ".";
+import { ChannelMemberStore, cl, GuildMemberCountStore, numberFormat, ThreadMemberListStore } from ".";
 import { OnlineMemberCountStore } from "./OnlineMemberCountStore";
 
 export function MemberCount({ isTooltip, tooltipGuildId }: { isTooltip?: true; tooltipGuildId?: string; }) {
@@ -30,10 +31,19 @@ export function MemberCount({ isTooltip, tooltipGuildId }: { isTooltip?: true; t
         () => ChannelMemberStore.getProps(guildId, currentChannel?.id)
     );
 
+    const threadGroups = useStateFromStores(
+        [ThreadMemberListStore],
+        () => ThreadMemberListStore.getMemberListSections(currentChannel.id)
+    );
+
     if (!isTooltip && (groups.length >= 1 || groups[0].id !== "unknown")) {
         onlineCount = groups.reduce((total, curr) => total + (curr.id === "offline" ? 0 : curr.count), 0);
     }
 
+    if (!isTooltip && threadGroups && !isObjectEmpty(threadGroups)) {
+        onlineCount = Object.values(threadGroups).reduce((total, curr) => total + (curr.sectionId === "offline" ? 0 : curr.userIds.length), 0);
+    }
+
     useEffect(() => {
         OnlineMemberCountStore.ensureCount(guildId);
     }, [guildId]);

src/plugins/memberCount/index.tsx

@@ -32,6 +32,10 @@ export const GuildMemberCountStore = findStoreLazy("GuildMemberCountStore") as F
 export const ChannelMemberStore = findStoreLazy("ChannelMemberStore") as FluxStore & {
     getProps(guildId: string, channelId: string): { groups: { count: number; id: string; }[]; };
 };
+export const ThreadMemberListStore = findStoreLazy("ThreadMemberListStore") as FluxStore & {
+    getMemberListSections(channelId: string): { [sectionId: string]: { sectionId: string; userIds: string[]; }; };
+};
+
 
 const settings = definePluginSettings({
     toolTip: {