用户名反应本地firebase

Question

如何在firebase数据库本机中检索和显示用户名。

import * as firebase from "firebase";
import { db } from '../auth/db';
let itemsRef = db.ref('/doxapp');

export default class Profil extends React.Component {
  state = {
    doxapp: []
  };

  componentDidMount() {
    itemsRef.on('value', snapshot => {
      let data = snapshot.val();
      let doxapp = Object.values(data);
      this.setState({ doxapp });
    });
  }