@isogon/prefetch

v0.1.1

Published

2 years ago

It allows you to do async actions before rendering the view.

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dweedon

terribleplan

isogon_user

redux react async props

Prefetch for React Router and Redux

Decorator and provider for handling async actions before route rendering in React.

yarn install prefetch

Notice

Prefetch is inspired by redux-connect

Usage

Prefetch is designed to work in combination with redux and react-router

Setup

import { Prefetcher }  from 'redux-prefetcher';

All you have to do is render Router with Prefetcher middleware

render((
  <Provider store={store}>
    <Router
      render={(props) => <Prefetcher {...props}/>}
      history={browserHistory}
    >
      <Route path="/" component={App}/>
    </Router>
  </Provider>
), el)

Prefetcher will watch for route changes, when they happen it will look for components used in that route that are wrapped with prefetch. If it finds any, it will block the display of those components until their prefetch actions are complete.

Example

Using redux-promise

Create an action and prefetch will dispatch them for you. Prefetch will dispatch whatever you return. Either your promise middleware or your Thunk needs to finally return a promise.

redux-promise returns promises by default so it works well with prefetch.

import { connect } from 'react-redux';
import { prefetch } from 'redux-prefetcher';

@prefetch(() => ({
  type: 'GET_LUNCH',
  payload: Promise.resolve({
    name: 'Fish Tacos',
    from: 'The Fish Taco Store'
  })
}))
@connect((state) => ({
  lunch: state.lunch
}))
function App({ lunch }) {
  return (
    <h4>Lunch Time!</h4>
    <div>Looks like you are having {lunch.name} from {lunch.from}</div>
  );
}

If you want to use redux-thunk, make sure to return a reference to your promise so that prefetch knows when your thunk is complete. That could look something like this.

...

@prefetch(() => (dispatch) => Promise.resolve(dispatch({
  type: 'GET_LUNCH',
  payload: {
    name: 'Fish Tacos',
    from: 'The Fish Taco Store'
  }
}));

...

Server Side rendering

Ideally you want to do all this asynchronous stuff on the server and preload all that data into state. There are only three things you need to do to get this to work.

Use the prefetchData helper method in your server code, It expects an object containing all renderProps and your redux store.
Use Prefetcher instead of RoutingContext and pass it renderProps
Set the prefetchedOnServer flag on both the client and server.

import { renderToString } from 'react-dom/server'
import { match, RoutingContext } from 'react-router'
import { Prefetcher, prefetchData } from 'redux-prefetcher';
import { Provider } from 'react-redux';
import { createStore, combineReducers } from 'redux';
import serialize from 'serialize-javascript';


import lunchReducer from './lunchReducer';

app.get('*', (req, res) => {
  const store = createStore(combineReducers({ lunch: lunchReducer }));

  match({ routes, location: req.url }, (err, redirect, renderProps) => {

    // 1. load data
    prefetchData({ ...renderProps, store }).then(() => {

      // 2. use `Prefetcher` instead of `RoutingContext` and pass it `renderProps`
      const appHTML = renderToString(
        <Provider store={store} key="provider">
          <Prefetcher {...renderProps} prefetchedOnServer />
        </Provider>
      )

      // 3. render the Redux initial data into the server markup
      const html = createPage(appHTML, store)
      res.send(html)
    })
  })
})

function createPage(html, store) {
  return `
    <!doctype html>
    <html>
      <body>
        <div id="app">${html}</div>

        <!-- its a Redux initial data -->
        <script dangerouslySetInnerHTML={{__html: `window.__data=${serialize(store.getState())};`}} charSet="UTF-8"/>
      </body>
    </html>
  `
}

// on the client
const component = (
  <Provider store={store}>
    <Router
      render={(props) => <Prefetcher {...props} prefetchedOnServer />}
      history={history}
      children={routes}
    />
  </Provider>
);

API

Notes

Usage with `applyRouterMiddleware`

// on the client
const render = applyRouterMiddleware(useScroll());
<Router
  render={(props) => <Prefetcher {...props} {render} />}
  history={history}
  routes={getRoutes(store)}
/>

Basically what you do is instead of using render method like:

const render = props => <RouterContext {...props} />;

you use

const render = applyRouterMiddleware(...middleware);

Collaboration

You're welcome to PR, and we appreciate any questions or issues, please open an issue!

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