React Firebase useAuth

useAuth.ts

import * as firebase from 'firebase/app'
import { useEffect, useState, createContext } from 'react'

export type AuthState = {
  initializing: boolean
  user: firebase.User | null
}

export const userContext = createContext<AuthState>({
  initializing: true,
  user: null,
})

export const useAuth = () => {
  const [state, setState] = useState<AuthState>({
    initializing: true,
    user: null,
  })

  useEffect(() => {
    const unsubscribe = firebase.auth().onIdTokenChanged(async (user) => {
      if (user) {
        const token = await user.getIdToken()
        localStorage.setItem('token', token)
      }
    })
    return () => unsubscribe()
  }, [])

  useEffect(() => {
    const unsubscribe = firebase.auth().onAuthStateChanged(async (user) => {
      if (user) {
        const token = await user.getIdToken()
        localStorage.setItem('token', token)
      }

      setState({ initializing: false, user })
    })

    return () => unsubscribe()
  }, [])

  return state
}