[英]Firebase realtime database record only one child
对于特定用途,我只想在实时数据库中保存一个元素,并且在修改时更新它,我不需要将所有更改保存为子项。 我有这段代码,但它创建了孩子。
<script type="module">
import {initializeApp} from "https://www.gstatic.com/firebasejs/9.6.6/firebase-app.js";
import {
getDatabase,
set,
ref,
push,
child,
onValue,
onChildAdded
} from "https://www.gstatic.com/firebasejs/9.6.6/firebase-database.js";
const firebaseConfig = {
apiKey: "...",
authDomain: "....firebaseapp.com",
databaseURL: "....firebaseio.com",
projectId: "...",
storageBucket: "...",
messagingSenderId: "...",
appId: "..."
};
// Initialize Firebase
const app = initializeApp(firebaseConfig);
const database = getDatabase(app);
submit.addEventListener('click', (e) => {
var message = document.getElementById('message').value;
//var name = myName;
const id = push(child(ref(database), 'messages')).key;
set(ref(database, 'messages/' + id), {
//name: name,
message: message
});
document.getElementById('message').value = "";
//alert('message has sent');
});
const dbRef = ref(getDatabase());
const newMsg = ref(database, 'messages/');
onChildAdded(newMsg, (data) => {
var divData = data.val().message;
let h1 = document.querySelector("h1");
h1.textContent = divData;
});
谢谢。
如果你不想创建一个子节点,你可以简单地写messages
:
set(ref(database, 'messages'), {
message: message
});
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