frontend/src/App.js

import ReactDOM from 'react-dom';
import React, { Component } from 'react';
import { HashRouter as Router, Route, Link } from "react-router-dom";
import  "./App.css"
import "./assets/comm.css"
import {Redirect} from "react-router-dom";

import login from './pages/login/login';
import home from './pages/home/home';
import errpage from "./pages/errpage/errpage"
export default class App extends Component {
  state = {
   pathname:'',
  };
  componentWillMount(){
      const pathname=window.location.href.lastIndexOf('\/');
      const pathnamestr=window.location.href.substr(pathname);
      this.setState({pathname:`${pathnamestr}`});
  }

  render() {
    return (
        <Router>        
          <Route  path="/login" exact={true} component={login} />  
          <Route  path="/home"  component={home} /> 
          <Route exact={true} path="/" render={
      ()=> (
      <Redirect to="/login"/>)}>
    </Route>
      <Route    component={errpage} /> 
      </Router>
    );
  }
}