我做了一個(gè) API fetch 來取回這些數(shù)據(jù)：{  "id": 1,  "name": "Apple",  "symbol": "AAPL",  "lastPrice": {    "id": 7,    "currentPrice": 116.03,    "openPrice": 115.55,    "highPrice": 116.75,    "lowPrice": 115.17,    "previousClosePrice": 115.17,    "timeOfRetrieval": "2020-11-26T19:04:35.150+00:00"  }}這是我的反應(yīng)代碼：function StockCard(props) {  const [API, setAPI] = useState("http://localhost:8080/stock/getquote/AAPL")  const [FetchInterval, setFetchInterval] = useState(300000)  const [StockData, setStockData] = useState({})  useEffect(() => {    FetchData();    const interval = setInterval(() => {      FetchData();    }, FetchInterval)    return() => clearInterval(interval);  }, [FetchInterval]);  const FetchData = async () =>{    console.log("FETCH CALLED");    const resp = await Axios.get(API);          setStockData(resp.data);            }    return(        <div>        <div className='card-container' style={{background: 'linear-gradient(to top, #141e30, #243b55)', padding: '4rem 1rem'}}>        <CryptoCard          currencyName={StockData.name}          currencyPrice={StockData.lastPrice.currentPrice}          icon={<img src="https://upload.wikimedia.org/wikipedia/commons/thumb/4/46/Bitcoin.svg/2000px-Bitcoin.svg.png"/>}          currencyShortName={StockData.symbol}          trend='(8.54%) $563.47'          trendDirection={1}          chartData={[9200, 5720, 8100, 6734, 7054, 7832, 6421, 7383, 8697, 8850]}        />        </div>        </div>    )}export default StockCard;它說無法在這一行讀取未定義的屬性“currentPrice”：currencyPrice={StockData.lastPrice.currentPrice}如果我僅注銷 StockData，那么我會(huì)獲取值，但無法從原始 JSON 對(duì)象獲取該內(nèi)部對(duì)象我究竟做錯(cuò)了什么？