我有2个防火基地的原材料和库存清单。库存列表包含具有原材料关键字的对象。我用那把钥匙去取原材料。我正在获取所有的库存列表，然后当我迭代列表中的每个对象以连接原材料时，问题是可观测对象只返回第一个对象。这意味着，它不会遍历所有列表。这是我的代码

rawMaterialsStocksRef: AngularFireList<any>;
  rawMaterialStockRef: AngularFireObject<any>;

  private dbPathStock = '/raw_material_stock';

  constructor(
    private db: AngularFireDatabase,
    private rawMaterialService: RawMaterialsManagementService
  ) {
    this.rawMaterialsStocksRef = db.list(this.dbPathStock);
  }

getRawMaterialStockList() {

   const rawData = this.rawMaterialsStocksRef.valueChanges().pipe(
      map(rawMaterialsStocks =>
        rawMaterialsStocks.map(stock => ({
         ...stock
        }))
      ),
      switchMap(stockArr => from(stockArr)), 
      // gives the following 
      // { "factoryKey": "34""quantity": "34", "rawMaterialKey": "-NDNPe47CDTbjmwGgW_3"}
      // { "factoryKey": "20", "quantity": "20", "rawMaterialKey": "-NDIjiVqKP-lLwJGwmic"}
      switchMap(stock =>
        // this service i use to fetch each raw material based on its key
        this.rawMaterialService.getRawMaterial(stock.rawMaterialKey).valueChanges()
          .pipe(
            map(rawMaterial => {
              return { ...stock, ...rawMaterial }
            })
          )
      ),
    );

   rawData.subscribe()
}

这是我得到的结果

{
    "factoryKey": "20",
    "quantity": "20",
    "rawMaterialKey": "-NDIjiVqKP-lLwJGwmic",
    "code": "KLL2311",
    "name": "Material 03"
}

如您所见，尽管数组包含多个对象，但我只成功连接了一次！
请帮帮我，我花了3天时间，什么都试过了，就是不管用！