Firebase应用已存在

Question

我正在创建一个Ionic 2应用，并且正在使用firebase并在运行应用时遇到此错误：

Firebase App named DEFAULT already exists [duplicate]

这是代码：

import { Component } from '@angular/core';
import { Platform } from 'ionic-angular';
import { StatusBar, Splashscreen } from 'ionic-native';
import { TabsPage } from '../pages/tabs/tabs';

import * as firebase from 'firebase';

export const firebaseConfig = {
    apiKey: "...",
    authDomain: "...",
    databaseURL: "...",
    storageBucket: "...",
    messagingSenderId: "..."
};

@Component({
  templateUrl: 'app.html'
})
export class MyApp {
  rootPage = TabsPage;

  constructor(platform: Platform) {
    platform.ready().then(() => {
      // Okay, so the platform is ready and our plugins are available.
      // Here you can do any higher level native things you might need.
      StatusBar.styleDefault();
      Splashscreen.hide();
    });
    firebase.initializeApp(firebaseConfig);
  }
}

当然这有我的火力信息，而不是'......'。 我做错了什么？