authState.js

import React from 'react'
import { BrowserRouter as Router, Route, Link, Redirect, withRouter } from 'react-router-dom'
import authState from './CoreComponents/authState'
import PrivateRoute from './CoreComponents/privateRoute'
import fakeAuth from './CoreComponents/fakeAuth'

const Public = () => <h3>Public</h3>
const Protected = () => <h3>Protected</h3>

class Login extends React.Component {
  state = {
    redirectToReferrer: false
  }
  login = () => {
    authState.authenticate((res) => {
      console.log(res)
    });
    fakeAuth.authenticate(() => {
      this.setState(() => ({
        redirectToReferrer: true
      }))
    })
    // authState.getUsers((res) => {
    //   console.log(res)
    // });
  }
  render() {
    const { from } = this.props.location.state || { from: { pathname: '/' } }
    const { redirectToReferrer } = this.state

    if (redirectToReferrer === true) {
      return <Redirect to={from} />
    }

    return (
      <div>
        <p>You must log in to view the page</p>
        <button onClick={this.login}>Log in</button>
      </div>
    )
  }
}

const AuthButton = withRouter(({ history }) => (
  fakeAuth.isAuthenticated ? (
    <p>
      Welcome! <button onClick={() => {
        fakeAuth.signout(() => history.push('/'))
      }}>Sign out</button>
    </p>
  ) : (
    <p>You are not logged in.</p>
  )
))

export default function AuthExample () {
  return (
    <Router>
      <div>
        <AuthButton/>
        <ul>
          <li><Link to="/public">Public Page</Link></li>
          <li><Link to="/protected">Protected Page</Link></li>
        </ul>
        <Route path="/public" component={Public}/>
        <Route path="/login" component={Login}/>
        <PrivateRoute path='/protected' component={Protected} />
      </div>
    </Router>
  )
}



module.exports = {

  authenticate: function(callback){
    var data = { email: "test@test.com", password:"123" }
    var url = "https://reqres.in/api/login";
    fetch(url, {
      method: 'POST',
      mode: 'CORS',
      body: JSON.stringify(data),
      headers: {'Content-Type': 'application/json'}
    }).then(res => res.json()).then((result) => {
      callback(result);
    }, (error) => {
      callback(result);
    });
  }

}