错误是：不变量违规：组件'div'的view config getter回调必须是一个函数（接收到'undefined'）。确保组件名称以大写字母开头。我在尝试从firebase检索数据到react native的表组件时遇到此错误，该组件是ReactTable，并且在控制台中查看数据时在控制台中给出空数组，因此输出中没有显示任何内容。

import React, { Component } from 'react';
import { StyleSheet, View, Text, Button } from 'react-native';
import ReactTable from 'react-table';
import firebase from 'firebase';

const firebaseConfig = {
...
};
firebase.initializeApp(firebaseConfig);

export default class Form1 extends Component {
constructor(props) {
    super(props);

    this.state = {
        data: [],
        columns: [
            {
                Header: "email",
                accessor: "email"
            },
            {
                Header: "password",
                accessor: "password"
            }
        ]
    }
}

componentDidMount() {
    const data = [];
    var query = firebase.database().ref("users");
    query.once("value").then((snapshot) => {
        snapshot.forEach((childSnapshot, index) => {
            let singleObj = {
                email: childSnapshot.val().email,
                password: childSnapshot.val().password,
            }
            data.push(singleObj);

            if (index === snapshot.length - 1) {
                this.setState({ data: data });
            }
        });
    });
}

render() {
    return (
        <div>
            {this.state.data.length > 0 && <ReactTable data={this.state.data} columns= 
{this.state.columns} />}
        </div>
    );
}
}

const styles = StyleSheet.create({
container: { flex: 1, padding: 16, paddingTop: 30, backgroundColor: '#fff' },
head: { height: 40, backgroundColor: '#f1f8ff' },
text: { margin: 6 }
});