Use FlairStore's cache for group naming

Turns out GroupStore doesn't really know much.

src/stores/CommunityPrototypeStore.ts

@@ -22,6 +22,8 @@ import { EffectiveMembership, getEffectiveMembership } from "../utils/membership
 import SettingsStore from "../settings/SettingsStore";
 import * as utils from "matrix-js-sdk/src/utils";
 import { UPDATE_EVENT } from "./AsyncStore";
+import FlairStore from "./FlairStore";
+import TagOrderStore from "./TagOrderStore";
 
 interface IState {
     // nothing of value - we use account data
@@ -43,6 +45,15 @@ export class CommunityPrototypeStore extends AsyncStoreWithClient<IState> {
         return CommunityPrototypeStore.internalInstance;
     }
 
+    public getSelectedCommunityName(): string {
+        return CommunityPrototypeStore.instance.getCommunityName(TagOrderStore.getSelectedPrototypeTag());
+    }
+
+    public getCommunityName(communityId: string): string {
+        const profile = FlairStore.getGroupProfileCachedFast(this.matrixClient, communityId);
+        return profile?.name || communityId;
+    }
+
     protected async onAction(payload: ActionPayload): Promise<any> {
         if (!this.matrixClient || !SettingsStore.getValue("feature_communities_v2_prototypes")) {
             return;

src/stores/FlairStore.js

@@ -148,6 +148,22 @@ class FlairStore extends EventEmitter {
         });
     }
 
+    /**
+     * Gets the profile for the given group if known, otherwise returns null.
+     * This triggers `getGroupProfileCached` if needed, though the result of the
+     * call will not be returned by this function.
+     * @param matrixClient The matrix client to use to fetch the profile, if needed.
+     * @param groupId The group ID to get the profile for.
+     * @returns The profile if known, otherwise null.
+     */
+    getGroupProfileCachedFast(matrixClient, groupId) {
+        if (this._groupProfiles[groupId]) {
+            return this._groupProfiles[groupId];
+        }
+        this.getGroupProfileCached(matrixClient, groupId);
+        return null;
+    }
+
     async getGroupProfileCached(matrixClient, groupId) {
         if (this._groupProfiles[groupId]) {
             return this._groupProfiles[groupId];