sbuggay · July 6, 2019 10:02 · Jul 6, 2019
diff --git a/BatchedRequester.ts b/BatchedRequester.ts
@@ -0,0 +1,72 @@
+type BatchedRequest<T> = (data: string[]) => Promise<T[]>;
+interface IRequestStore<T> {
+    promise: Promise<T>;
+    resolve: Function;
+}
+
+export class BatchedSteamRequester<T> {
+    private _requests: { [index: string]: IRequestStore<T> };
+    private _interval: NodeJS.Timeout;
+    private _batchedRequest: BatchedRequest<T>;
+    private _mapToRequest: (obj: T) => string;
+
+    constructor(batchedRequest: (BatchedRequest<T>), mapToRequest: (obj: T) => string, interval: number) {
+        this._batchedRequest = batchedRequest;
+        this._mapToRequest = mapToRequest;
+        this._interval = setInterval(this._flushRequests.bind(this), interval);
+        this._requests = {};
+    }
+
+    /**
+     * Queue up a request to be made, return the promise.
+     *
+     * @param {T} data
+     * @returns {Promise<T>}
+     * @memberof BatchedSteamRequester
+     */
+    public request(data: string): Promise<T> {
+
+        // If this has already been requested, return the previously generated promise
+        if (this._requests[data]) {
+            return this._requests[data].promise;
+        }
+
+        let retainedResolve = () => {};
+        const promise = new Promise<T>((resolve) => {
+            retainedResolve = resolve;
+        });
+
+        this._requests[data] = {
+            promise,
+            resolve: retainedResolve
+        }
+
+        return promise;
+    }
+
+    /**
+     * Clear interval and request queue.
+     *
+     * @memberof BatchedSteamRequester
+     */
+    public tearDown() {
+        clearInterval(this._interval);
+        this._requests = {};
+    }
+
+    /**
+     * Flush request queue. Batch each and send to set request, resolve all batched promise resolves.
+     *
+     * @private
+     * @memberof BatchedSteamRequester
+     */
+    private async _flushRequests() {
+        if (Object.keys(this._requests).length <= 0) return;
+        const data = Object.keys(this._requests);
+        const response = await this._batchedRequest(data);
+        response.forEach((r) => {
+            const key = this._mapToRequest(r);
+            this._requests[key].resolve(r);
+        });
+    }
+}