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[英]React error "Objects are not valid as a React child (found: [object Promise])"
[英]How to fix Error: Objects are not valid as a React child (found: [object Promise])
Objects are not valid as a React child (found: [object Promise]). If you meant to render a collection of children, use an array instead.
in ul (at ChatRoom.js:16)
由於某種原因,它會引發此錯誤。 這是我的代碼:
const [messages] = useCollectionData(query, { idField: 'id' });
return (
<div className={classes.ChatRoomContainer}>
<ul>
{messages ? messages && messages.map(async msg => {
const messageClass = msg.userId === props.userId ? classes.Sent : classes.Recieved;
let username;
await firebase.firestore().collection('users').doc(msg.author).get().then(doc => {
username = doc.data().userName;
});
return <li className={messageClass + ' ' + classes.Message} key={msg.id}>
<label>{msg.author !== props.userId ? username : 'You'}</label>
<p className={classes.MessageContent}>{msg.messageContent}</p>
</li>
}) : <p>Loading...</p>}
</ul>
<form className={classes.Form} onSubmit={(e) => props.onMessageSentHandler(e)}>
<input className={classes.Input} placeholder="Type your message..." onChange={(e) => props.onInputChangedHandler(e)} value={props.messageInput} />
<button className={classes.Btn}><FontAwesomeIcon color="white" icon='paper-plane' className={classes.PaperPlaneIcon} /></button>
</form>
</div>
)
有什么辦法可以解決嗎? 僅當我順便使用 async 時才會出現。
您正在嘗試執行 Promise 兩次。
async/await
和.then().catch
是兩種不同的語法。
嘗試這個:
let doc = await firebase.firestore().collection('users').doc(msg.author).get();
然后從中讀取用戶名:
return (
<li className={messageClass + ' ' + classes.Message} key={msg.id}>
<label>{msg.author !== props.userId ? doc.data().username : 'You'}</label>
<p className={classes.MessageContent}>{msg.messageContent}</p>
</li>
)
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