這個 js reduce 可以很好地處理查詢結果：function toc(current) {  return {....};};function getToc(data) {  return = data.reduce((a, c) => Object.assign(a, {[c.id]: toc(c)}), {});};const query = db.collection(normCollection).where('a_id', '==', a_id ).where('year', '==', year) .orderBy("id");subscriptionNorm = collectionData(query, "id").subscribe(data => console.log(getToc(data)));但是當我使用 RxJs reduce 時，它停止工作了。它與流結束有關，但是......但是我不明白 RxFire / RxJs 如何處理流式 firestore 查詢結果：...subscriptionNorm = collectionData(query, "id").pipe(reduce((a, c) => Object.assign(a, {[c.id]: toc(c)}), {})).subscribe(data => console.log(data));更新這個工作正常，但是......：...subscriptionNorm = collectionData(query, "id").pipe(  map(v => v.reduce((a, c) =>     Object.assign(a, {[c.id]: toc(c)}), {})  ),).subscribe(data => console.log(data));