Usage with React Router

is available on npm . This guides assumes you are using react-router-dom@^4.1.1.

npm install —save react-router-dom

Configuring the Fallback URL

Before integrating React Router, we need to configure our development server. Indeed, our development server may be unaware of the declared routes in React Router configuration. For example, if you access /todos and refresh, your development server needs to be instructed to serve index.html because it is a single-page app. Here's how to enable this with popular development servers.

If you are serving your index.html from Express:

If you are serving your index.html from WebpackDevServer:You can add to your webpack.config.dev.js:

devServer: {
  historyApiFallback: true
}

Along this chapter, we will be using the Todos example. We recommend you to clone it while reading this chapter.

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

In a React app, usually you would wrap <Route /> in <Router /> so that when the URL changes, <Router /> will match a branch of its routes, and render their configured components. <Route /> is used to declaratively map routes to your application's component hierarchy. You would declare in path the path used in the URL and in component the single component to be rendered when the route matches the URL.

const Root = () => (
  <Router>
    <Route path="/" component={App} />
  </Router>
)

However, in our Redux App we will still need <Provider />. <Provider /> is the higher-order component provided by React Redux that lets you bind Redux to React (see ).

We will then import the <Provider /> from React Redux:

We will wrap <Router /> in <Provider /> so that route handlers can get access to the store.

const Root = ({ store }) => (
  <Provider store={store}>
    <Router>
      <Route path="/" component={App} />
    </Router>
)

Now the <App /> component will be rendered if the URL matches '/'. Additionally, we will add the optional :filter? parameter to /, because we will need it further on when we try to read the parameter :filter from the URL.

<Route path="/:filter?" component={App} />

components/Root.js

import React from 'react'
import { Provider } from 'react-redux'
import { BrowserRouter as Router, Route } from 'react-router-dom'
import App from './App'
const Root = ({ store }) => (
  <Provider store={store}>
    <Router>
      <Route path="/:filter?" component={App} />
    </Router>
  </Provider>
)
Root.propTypes = {
  store: PropTypes.object.isRequired
}
export default Root

We will also need to refactor index.js to render the <Root /> component to the DOM.

index.js

Navigating with React Router

React Router comes with a <Link /> component that lets you navigate around your application. If you want to add some styles, react-router-dom has another special <Link /> called , which accepts styling props. For instance, the activeStyle property lets us apply a style on the active state.

containers/FilterLink.js

import React from 'react'
import { NavLink } from 'react-router-dom'
const FilterLink = ({ filter, children }) => (
  <NavLink
    to={filter === 'SHOW_ALL' ? '/' : `/${filter}`}
    activeStyle={{
      color: 'black'
    }}
  >
    {children}
  </NavLink>
)
export default FilterLink

components/Footer.js

import FilterLink from '../containers/FilterLink'
import { VisibilityFilters } from '../actions'
const Footer = () => (
  <p>
    Show: <FilterLink filter={VisibilityFilters.SHOW_ALL}>All</FilterLink>
    {', '}
    <FilterLink filter={VisibilityFilters.SHOW_ACTIVE}>Active</FilterLink>
    {', '}
    <FilterLink filter={VisibilityFilters.SHOW_COMPLETED}>Completed</FilterLink>
  </p>
)
export default Footer

Now if you click on <FilterLink /> you will see that your URL will change between '/SHOW_COMPLETED', '/SHOW_ACTIVE', and '/'. Even if you are going back with your browser, it will use your browser's history and effectively go to your previous URL.

Currently, the todo list is not filtered even after the URL changed. This is because we are filtering from <VisibleTodoList />'s mapStateToProps(), which is still bound to the state and not to the URL. mapStateToProps has an optional second argument ownProps that is an object with every props passed to <VisibleTodoList />

containers/VisibleTodoList.js

const mapStateToProps = (state, ownProps) => {
  return {
    todos: getVisibleTodos(state.todos, ownProps.filter) // previously was getVisibleTodos(state.todos, state.visibilityFilter)
  }
}

Right now we are not passing anything to <App /> so ownProps is an empty object. To filter our todos according to the URL, we want to pass the URL params to <VisibleTodoList />.

When previously we wrote: <Route path="/:filter?" component={App} />, it made available inside App a params property.

params property is an object with every param specified in the url with the match object. e.g: match.params will be equal to { filter: 'SHOW_COMPLETED' } if we are navigating to localhost:3000/SHOW_COMPLETED. We can now read the URL from <App />.

Note that we are using on the properties to pass in params to .

components/App.js

Next Steps

Now that you know how to do basic routing, you can learn more about React Router API