未捕獲的型別錯誤：無法添加屬性0，物件在Array.push處不可擴展

從 firebase 獲取資料并將資料推送到陣列時出現此錯誤。在這里，當我將 firebase onValue 中的資料推送到此臨時陣列時，我定義了一個臨時陣列我收到此錯誤 Uncaught TypeError: Cannot add property 0, object is not extensible at Array.push。這是我的代碼

function Room() {
const [textInput, setTextInput] = useState('');
const temp = [];

const handleTextInputChange = (event) => {
    setTextInput(event.target.value);
};

const handleSubmit = () => {
    console.log('here goes');
    if (textInput !== '') {
        const refer = ref(database, 'rooms/');
        push(refer, textInput).then(() => {
            setTextInput('');
            toast.success('Added Successfully!');
        });
    }
};

useEffect(() => {
    const refer = ref(database, 'rooms/');
    onValue(refer, (snap) => {
        snap.forEach((child) => {
            console.log(child.val()   child.key);
            // I am getting error in this line
            temp.push({ id: child.key, firstName: child.val() });
        });
    });
}, []);

return (
  <div>
    <Grid item xs={12}>
                <SubCard title="Room List">
                    <div style={{ height: 400, width: '100%' }}>
                        <DataGrid
                            rows={temp}
                            columns={columns}
                            pageSize={5}
                            rowsPerPageOptions={[5]}
                            components={{
                                Toolbar: CustomToolbar
                            }}
                        />
                    </div>
                </SubCard>
            </Grid>
  </div>
)

uj5u.com熱心網友回復：

當您嘗試推送到凍結陣列時，您得到的錯誤是：

const temp = Object.freeze([]);
temp.push(42);

您已經證明您正在將陣列傳遞給DataGridas rows。顯然，DataGrid凍結陣列，大概是因為它需要知道它的內容不會改變。

如果要更改這些內容，則需要將其存盤temp在 state 中并在添加后重新渲染；查看***評論（我也重命名temp為dataGridRows）：

function Room() {
    const [textInput, setTextInput] = useState('');
    // *** Store it in state
    const [dataGridRows, setDataGridRows] = useState([]);

    const handleTextInputChange = (event) => {
        setTextInput(event.target.value);
    };

    const handleSubmit = () => {
        console.log('here goes');
        if (textInput !== '') {
            const refer = ref(database, 'rooms/');
            push(refer, textInput).then(() => {
                setTextInput('');
                toast.success('Added Successfully!');
            });
        }
    };

    useEffect(() => {
        const refer = ref(database, 'rooms/');
        onValue(refer, (snap) => {
            snap.forEach((child) => {
                console.log(child.val()   child.key);
                // *** Add to it in state; this will cause a re-render
                // so DataGrid picks up the change
                setDataGridRows(dataGridRows => [...dataGridRows, { id: child.key, firstName: child.val() }];
            });
        });
    }, []);

    return (
        <div>
            <Grid item xs={12}>
                <SubCard title="Room List">
                    <div style={{ height: 400, width: '100%' }}>
                        <DataGrid
                            rows={dataGridRows}
                            columns={columns}
                            pageSize={5}
                            rowsPerPageOptions={[5]}
                            components={{
                                Toolbar: CustomToolbar
                            }}
                        />
                    </div>
                </SubCard>
            </Grid>
        </div>
    )
}

標籤：javascript 反应 火力基地 Firebase 实时数据库

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