FAQ.md

Frequently Asked Questions

---

• How to navigate with Redux action
• How to get the current browser location (URL)
• How to set Router props e.g. basename, initialEntries, etc.
• How to hot reload functional components
• How to hot reload reducers
• How to support Immutable.js

How to navigate with Redux action

with store.dispatch

import { push } from 'connected-react-router'

store.dispatch(push('/path/to/somewhere'))

in redux thunk

import { push } from 'connected-react-router'

export const login = (username, password) => (dispatch) => {

  /* do something before redirection */

  dispatch(push('/home'))
}

in redux saga

import { push } from 'connected-react-router'
import { put, call } from 'redux-saga/effects'

export function* login(username, password) {

  /* do something before redirection */

  yield put(push('/home'))
}

How to get the current browser location (URL)

The current browser location can be accessed directly from the router state with react-redux's connect. The location object is comprised of pathname, search (query string), and hash.

import { connect } from 'react-redux'

const Child = ({ pathname, search, hash }) => (
  <div>
    Child receives
    <div>
      pathname: {pathname}
    </div>
    <div>
      search: {search}
    </div>
    <div>
      hash: {hash}
    </div>
  </div>
)

const mapStateToProps = state => ({
  pathname: state.router.location.pathname,
  search: state.router.location.search,
  hash: state.router.location.hash,
})

export default connect(mapStateToProps)(Child)

How to set Router props (e.g. basename, initialEntries, etc.)

You can pass props to the create*History functions of your choice (createBrowserHistory, createHashHistory, createMemoryHistory)

import { createBrowserHistory } from 'history'

const history = createBrowserHistory({
  basename: '/prefix/',
})

import { createHashHistory } from 'history'

const history = createHashHistory({
  hashType: 'slash',
  getUserConfirmation: (message, callback) => callback(window.confirm(message))
})

import { createMemoryHistory } from 'history'

const history = createMemoryHistory({
  initialEntries: [ '/one', '/two', { pathname: '/three' } ],
  initialIndex: 1
})

How to hot reload functional components

1. Save the main app component in its own file.

App.js

import React from 'react'
import { Route, Switch } from 'react-router' /* react-router v4 */
import { ConnectedRouter } from 'connected-react-router'

const App = ({ history }) => ( /* receive history object via props */
  <ConnectedRouter history={history}>
    <div>
      <Switch>
        <Route exact path="/" render={() => (<div>Match</div>)} />
        <Route render={() => (<div>Miss</div>)} />
      </Switch>
    </div>
  </ConnectedRouter>
)

export default App

2. Wrap the App component with AppContainer from react-hot-loader v3 as a top-level container.

index.js

import React from 'react'
import ReactDOM from 'react-dom'
import { Provider } from 'react-redux'
import { AppContainer } from 'react-hot-loader' /* react-hot-loader v3 */
import App from './App'
...
const render = () => { // this function will be reused
  ReactDOM.render(
    <AppContainer> { /* AppContainer for hot reloading v3 */ }
      <Provider store={store}>
        <App history={history} /> { /* pass history object as props */ }
      </Provider>
    </AppContainer>,
    document.getElementById('react-root')
  )
}

render()

3. Detect change and re-render with hot reload.

index.js

...
if (module.hot) {
  module.hot.accept('./App', () => {
    /* For Webpack 2.x
       Need to disable babel ES2015 modules transformation in .babelrc
       presets: [
         ["es2015", { "modules": false }]
       ]
    */
    render()

    /* For Webpack 1.x
    const NextApp = require('./App').default
    renderWithHotReload(NextApp)
    */
  })
}

Now, when you change any component that App depends on, it will trigger hot reloading without losing redux state. Thanks react-hot-loader v3!

How to hot reload reducers

Detect change and replace with a new root reducer with router state

index.js

...
if (module.hot) {
  module.hot.accept('./reducers', () => {
    /* For Webpack 2.x
       Need to disable babel ES2015 modules transformation in .babelrc
       presets: [
         ["es2015", { "modules": false }]
       ]
    */
    store.replaceReducer(connectRouter(history)(rootReducer))

    /* For Webpack 1.x
    const nextRootReducer = require('./reducers').default
    store.replaceReducer(connectRouter(history)(nextRootReducer))
    */
  })
}

How to support Immutable.js

1. Use combineReducers from redux-immutable to create the root reducer.

import { combineReducers } from 'redux-immutable'
...
const rootReducer = combineReducers({
  ...
})
...

2. Import ConnectedRouter, routerMiddleware, and connectRouter from connected-react-router/immutable instead of connected-react-router.

import { ConnectedRouter, routerMiddleware, connectRouter } from 'connected-react-router/immutable'

3. (Optional) Initialize state with Immutable.Map()

import Immutable from 'immutable'
...
const initialState = Immutable.Map()
...
const store = createStore(
  connectRouter(history)(rootReducer),
  initialState,
  ...
)