How to use the react-router-transition.presets.slideLeft function in react-router-transition

import { Router, Route, IndexRoute, browserHistory } from 'react-router';

import { RouteTransition, presets } from 'react-router-transition';

import Home from 'home';
import Header from 'header';
import Flight from 'flight';
import FlightList from 'flightlist';
import Train from 'train';
import Hotel from 'hotel';

if (module.hot && process.env.NODE_ENV === 'dev-HMR') module.hot.accept();

// console.log('process.env.NODE_ENV in Front-end:', process.env.NODE_ENV);

var styles = presets.slideLeft;

var App = function({ children, location }) {
  styles = location.action === 'POP' ? presets.slideRight : presets.slideLeft;
  // console.log(location.action);
  return (
  <div>
    <header>

    
      {children}
    
</header></div>

import React from 'react';
import { render } from 'react-dom';
import { Router, browserHistory } from 'react-router';

import { RouteTransition, presets } from 'react-router-transition';

import Header from './components/header';

// import Home from './home'; // Load on demand
// import Detail from './detail';
// import List from './list';
// import New from './new';

if (module.hot && process.env.NODE_ENV === 'dev-HMR') module.hot.accept();

var styles = presets.slideLeft;

const App = function({ children, location }) {
  styles = location.action === 'POP' ? presets.slideRight : presets.slideLeft;
  return (
    <div>
      <header>
      
        {children}
      
    </header></div>
  );

const getTransition = (location) => {
  let transition = presets.slideRight

  if (prevLocation && isAfter(prevLocation.pathname, location.pathname)) {
    transition = presets.slideLeft
  }

  prevLocation = location

  return transition
}