nuxtjs firebase plugin

firebase.js

import firebase from 'firebase/app'
import 'firebase/firestore'
import 'firebase/auth'
import 'firebase/storage'

export default ({ app }, inject) => {
  const env = process.browser ? app.store.state.env : process.env
  //   init firebase
  if (!firebase.apps.length && env.API_KEY && env.PROJECT_ID && env.SENDER_ID) {
    const config = {
      apiKey: env.API_KEY,
      authDomain: `${env.PROJECT_ID}.firebaseapp.com`,
      databaseURL: `https://${env.PROJECT_ID}.firebaseio.com`,
      projectId: env.PROJECT_ID,
      storageBucket: `gs://${env.PROJECT_ID}.appspot.com`,
      messagingSenderId: env.SENDER_ID
    }
    firebase.initializeApp(config)
  }
  // inject firebase services to application
  inject('DB', firebase.firestore())
  inject('auth', firebase.auth())
  inject('storage', firebase.storage())
  inject('emailProvider', new firebase.auth.EmailAuthProvider())
  inject('firebase', firebase)
}