index.js

import React from 'react'

import { Context } from '../lib/context'
import { firebase } from '../lib/firebase'

export default class Home extends React.Component {
  constructor (props) {
    super(props)
    this.state = {
      email: '',
      password: ''
    }
  }

  render () {
    return (
      <Context.Consumer>
        {store => {
          console.log(store)
          if (!store.currentUser.uid) {
            return (
              <div>
                <input placeholder='Email' onChange={e => this.setState({ email: e.target.value })} value={this.state.email} />
                <input type='password' placeholder='Password' onChange={e => this.setState({ password: e.target.value })} value={this.state.password} />
                <button onClick={() => firebase.auth().createUserWithEmailAndPassword(this.state.email, this.state.password)}>Submit</button>
              </div>
            )
          }
          return (
            <div>
              <div>Email: {store.currentUser.email}</div>
              <button onClick={() => store.signOut()}>Sign out</button>
            </div>
          )
        }}
      </Context.Consumer>
    )
  }
}