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React Router 4

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React Router 4

01 create-react-app

We use the Facebook React Boilerplate to get started:

create-react-app react-router-4

02 react-bootstrap

And add some Bootstrap for styling:

npm install --save react-bootstrap

We can now add the Bootsrap CSS inside the head of ./public/index.html :

<link rel='stylesheet' href='https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css' integrity='sha384-PsH8R72JQ3SOdhVi3uxftmaW6Vc51MKb0q5P2rRUpPvrszuE4W1povHYgTpBfshb' crossorigin='anonymous'>

And the Javascript at the end of the body tag:

<script src='https://code.jquery.com/jquery-3.2.1.slim.min.js' integrity='sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN' crossorigin='anonymous'></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.3/umd/popper.min.js' integrity='sha384-vFJXuSJphROIrBnz7yo7oB41mKfc8JzQZiCq4NCceLEaO4IHwicKwpJf9c9IpFgh' crossorigin='anonymous'></script>
<script src='https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js' integrity='sha384-alpBpkh1PFOepccYVYDB4do5UnbKysX5WZXm3XxPqe5iKTfUKjNkCk9SaVuEZflJ' crossorigin='anonymous'></script>

To add a simple Navbar on top, we will now replace the default create-react-app JSX inside ./src/coponents/app.js with a Bootstrap Navbar from their Example list (remember to replace all instances of class with className!):

return (
  <div className='App'>
    <nav className='navbar navbar-expand-md navbar-dark bg-dark fixed-top mb'>
      <a className='navbar-brand' href='#'>React Router 4</a>
      <button className='navbar-toggler' type='button' data-toggle='collapse' data-target='#navbarsExampleDefault' aria-controls='navbarsExampleDefault' aria-expanded='false' aria-label='Toggle navigation'>
        <span className='navbar-toggler-icon'></span>
      </button>

      <div className='collapse navbar-collapse' id='navbarsExampleDefault'>
        <ul className='navbar-nav mr-auto'>
          <li className='nav-item active'>
            <a className='nav-link' href='#'>Page 1 <span className='sr-only'>(current)</span></a>
          </li>
          <li className='nav-item'>
            <a className='nav-link' href='#'>Page 2</a>
          </li>
        </ul>
      </div>
    </nav>

    <div className='jumbotron mt'>
      <div className='col-sm-8 mx-auto mt'>
        <h1>This is just a Test</h1>
        <p>
          <a className='btn btn-primary' href='#' role='button'>View navbar docs &raquo;</a>
        </p>
      </div>
    </div>

  </div>
);

Now start the app with:

npm start

The Bootstrap Navbar should now show up in our React app on locallhost:3000:

03 react-router-dom

We can now use the basic example from the reacttraining.com website to add some routing to our app. First install the web based router - which is now called react-router-dom:

npm install --save react-router-dom

To add links to our navigation, we will need the <NavLink/> component, which is special version of the <Link/> that will add styling attributes to the rendered element when it matches the current URL (activeState). Replace all:

<a href='#'></a>

with

<NavLink to='#'></NavLink>

and import <NavLink /> from react-router-dom:

import { NavLink } from 'react-router-dom'

We created two links to two components, aptly named /page-1 and /page-2, that we now have to create inside the ./src/components directory. For <PageOne /> we want to use an ES6 Class Component to render some JSX:

import React, {Component} from 'react'
import { Link } from 'react-router-dom'
import { Button } from 'react-bootstrap'

class PageOne extends Component {
  render() {
    return (
        <div className='jumbotron mt'>
          [...]
        </div>
    );
  }
}

export default PageOne

And for <PageTwo /> we use a Stateless Component:

import React from 'react'
import { Link } from 'react-router-dom'
import { Button } from 'react-bootstrap'


const PageTwo = () => (
    <div className='jumbotron mt'>
      [...]
    </div>
)

export default PageTwo

Make sure to import all components in ./src/index.js:

import App from './App';
import PageOne from './PageOne';
import PageTwo from './PageTwo';

As well as adding the Router itself:

import {
  BrowserRouter as Router,
  Route,
  Link
} from 'react-router-dom'

Now we can copy the navigation (everything inside the <nav> tag) from ./src/components/app.js to ./src/index.js and replace the <App /> component that was placed there by create-react-app. Then wrap the JSX into a <Router> tag:

render(
  <Router>
    <div className='container'>
      <nav className='navbar navbar-expand-md navbar-dark bg-dark fixed-top mb'>
        <NavLink className='navbar-brand' to='/'> <img src={Logo} alt='React Router v4' /> </NavLink>

        <button className='navbar-toggler' type='button' data-toggle='collapse' data-target='#navbarsExampleDefault' aria-controls='navbarsExampleDefault' aria-expanded='false' aria-label='Toggle navigation'>
          <span className='navbar-toggler-icon'></span>
        </button>

        <div className='collapse navbar-collapse'>
          <ul className='navbar-nav mr-auto'>
            <li className='nav-item'>
              <NavLink className='nav-link' to='/page-1'>Page 1</NavLink>
            </li>
            <li className='nav-item'>
              <NavLink className='nav-link' to='/page-2'>Page 2</NavLink>
            </li>
          </ul>
        </div>
      </nav>

      <Route exact path='/' component={App}/>
      <Route path='/page-1' component={PageOne}/>
      <Route path='/page-2' component={PageTwo}/>
    </div>
  </Router>,

document.getElementById('root'))

04 Nested Routes

To create nested routes in React Router v4, we just have to add more routes inside a component. E.g. you have a route that leads the user from / to /chapter1, rendering the <Chapter1 /> component. To create a route to a nested article inside the chapter, like /chapter1/subarticle1, we now have to add further routes with the ${match.url} attribute inside the <Chapter1 />:

<NavLink to={`${match.url}/subarticle1`} />
<Route path={`${match.url}/subarticle1`} component={SubArticle1}/>

So lets add another Link and Route to the Nav component in ./src/index.js to render another component, called <NestedRoutes />, under /nested-routes. This is going to be our parent component for two nested routes/components: <PageOneNested /> and <PageTwoNested /> rendered under ./nested-routes/page-1-nested and ./nested-routes/page-2-nested, respectively.

import React from 'react'
import { Route, NavLink, Link } from 'react-router-dom'

import PageOneNested from './PageOneNested'
import PageTwoNested from './PageTwoNested'

const Topics = ({ match }) => (

    <div className='container-fluid'>
      <div className='row'>
        <nav className='nav nav-pills nav-fill col-sm-3 col-md-2 d-none d-sm-block bg-light sidebar'>
          <div className='clearfix'><br/><br/><br/></div>
          <Link className='nav-item nav-link' to={match.url}>
            <h3>Nested Routes</h3>
            <hr/>
          </Link>
          <NavLink className='nav-item nav-link' to={`${match.url}/page-1-nested`}>
            NestOne
          </NavLink>
          <NavLink className='nav-item nav-link' to={`${match.url}/page-2-nested`}>
            NestTwo
          </NavLink>
        </nav>

        <main role='main' className='col-sm-9 ml-sm-auto col-md-10 pt-3'>
          <div className='clearfix'><br/><br/><br/></div>
          <h1>Dashboard</h1>
          <Route path={`${match.url}/page-1-nested`} component={PageOneNested}/>
          <Route path={`${match.url}/page-2-nested`} component={PageTwoNested}/>
          <Route exact path={match.url} render={() => (
            <div>
              [...]
            </div>
          )}/>
        </main>
      </div>
    </div>
)

export default Topics

You can create the two files PageOneNested.js and PageTwoNested.js inside ./src/components. Just copy and paste the content from PageOne.js or PageTwo.js and change the component names, inside the file to PageOneNested and PageTwoNested.

React Router 4

Clicking on the NestOne or NestTwo link will load the components <PageOneNested /> or <PageTwoNested /> in the <main> area of the screen, under the Dashboard title - awesome !

05 Loading Animations

The react-transition-group is an easy way to perform animations when a React component enters or leaves the DOM.

npm install react-transition-group --save

https://hackernoon.com/animated-page-transitions-with-react-router-4-reacttransitiongroup-and-animated-1ca17bd97a1a https://medium.com/appifycanada/animations-with-reacttransitiongroup-4972ad7da286 https://github.com/reactjs/react-transition-group/tree/v1-stable