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[英]How to write data in Firebase Realtime Database as [custom key : value] in React?
[英]Write fetched data to variable from firebase realtime database react
我試圖將獲取的數據保存到變量中,但我總是得到“太多重新渲染”或“未定義”。 我做錯了什么
import {
child,
get,
getDatabase,
ref,
} from "firebase/database";
const db = getDatabase();
function App() {
const [data, setData] = useState();
const getData = ref(db);
useEffect(() => {
const fetch = () => {
get(child(getData, "tokens/")).then((snapshot) => {
const fetched = snapshot.val();
setData(fetched);
});
setTimeout(() => {
console.log(data);
}, 500);
};
fetch();
}, []);
}
不需要setTimeout()
。 解析promise后可以打印數據如下圖:
function App() {
const [data, setData] = useState();
const getData = ref(db);
useEffect(() => {
const fetchData = () => {
get(child(getData, "tokens/")).then((snapshot) => {
const fetched = snapshot.val();
console.log(fetched)
setData(fetched);
});
};
fetchData();
}, []);
}
此外,我已將 fetch 重命名為 function 以避免與Fetch API混淆
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