Add debounceRequest function

src/components/intent.ts

@@ -125,6 +125,7 @@ export class Intent {
         ensureClientSyncingCallback: () => Promise<void>;
     };
     private readyPromise?: Promise<unknown>;
+    private readonly debouncedRequests = new Map<string, Promise<unknown>>();
 
     /**
     * Create an entity which can fulfil the intent of a given user.
@@ -865,6 +866,31 @@ export class Intent {
         }
     }
 
+    /**
+     * Debounce a request to the intent
+     * @param requestKey A unique key name for the request. E.g. "bridge-channel-id"
+     * @param fnName A function on this object. E.g. "joinRoom"
+     * @param args Args to pass to the function.
+     * @returns A object containing the promise and a function to clear the value.
+     */
+    public debounceRequest<T>(requestKey: string, fnName: keyof Intent, ...args: unknown[])
+        : { promise: Promise<T>, clear?: () => void } {
+        if (fnName === "debounceRequest") {
+            throw Error('Cannot debounce this function');
+        }
+        const key = `${fnName}:${requestKey}`;
+        const existing = this.debouncedRequests.get(key);
+        if (existing) {
+            return { promise: existing as Promise<T> };
+        }
+        const promise = this[fnName](...args);
+        this.debouncedRequests.set(key, promise);
+        return {
+            promise,
+            clear: () => { this.debouncedRequests.delete(key) }
+        };
+    }
+
     // Guard a function which returns a promise which may reject if the user is not
     // in the room. If the promise rejects, join the room and retry the function.
     private async _joinGuard<T>(roomId: string, promiseFn: () => Promise<T>): Promise<T> {