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Expo

Fast Refresh with Expo Web! 🏃🏻‍♂️🔄

evanbacon profile image Evan Bacon ・Updated on ・3 min read

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If you've used Expo on iOS or Android recently you've probably used Fast Refresh (by Dan Abramov) to achieve stateful hot reloading during development. But how do you use Fast Refresh with Expo for web.?.. (Pretty easily).

On web this will update the DOM without reloading the page, this means the state will remain the same across updates. To fully update you can simply reload the window with ⌘ + R.

🤔 How to use

Currently there's no official Fast Refresh Webpack plugin, but you can get started today using a great community plugin by Michael Mok!

  • Bootstrap a new universal React Native project:
    • Expo: expo init then select any project
    • Other: npx create-react-native-app
  • Install the community Fast Refresh package:
    • yarn add -D @pmmmwh/react-refresh-webpack-plugin webpack-hot-middleware
  • Eject the Webpack config:
    • expo customize:web
  • In your newly created webpack.config.js:
const createExpoWebpackConfigAsync = require("@expo/webpack-config");
const ReactRefreshWebpackPlugin = require("@pmmmwh/react-refresh-webpack-plugin");

module.exports = async function (env, argv) {
  const config = await createExpoWebpackConfigAsync(env, argv);

  // Use the React refresh plugin in development mode
  if (env.mode === "development") {
    config.plugins.push(
      new ReactRefreshWebpackPlugin({ disableRefreshCheck: true })
    );
  }

  return config;
};
  • Now in your babel.config.js:
module.exports = function (api) {
  // This caches the Babel config by environment.
  api.cache.using(() => process.env.NODE_ENV);

  return {
    presets: ["babel-preset-expo"],
  };
};
  • Now run expo start:web to use it!

💡 BTW

When the official React fast refresh has been released, we will work on unifying it with native to create a universal solution. Until then this is a pretty nifty little feature! :]

Why share now then?

I got the idea for this tutorial from my friend Tim Neutkens of Next.js. I highly recommend using Next.js with Expo for web especially for navigation!

👋 That's all

Thanks for reading, that's all I've got for you today. Let me know if you enjoyed this article, and reach out if you have any more questions!

Discussion

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raarts profile image
Ron Arts

This was the result for me (though I didn't do this on a new project, but an existing one):

Invalid options object. React Refresh Plugin has been initialized using an options object that does not match the API schema.

  • options has an unknown property 'disableRefreshCheck'. These properties are valid: object { exclude?, forceEnable?, include?, overlay?, useLegacyWDSSockets? }
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younes0 profile image
Younes Bieche

remove disableRefreshCheck (deprecated option)

if (env.mode === 'development') {
  config.plugins.push(new ReactRefreshWebpackPlugin())
}
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walidvb profile image
Walid

I also couldn't make it work, both with @expo/webpack-config 0.12.20 and @expo/webpack-config 0.12.17.

My save does trigger a new compilation, but the webpack message sent via websocket to the browser is {"type": "invalid"}

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benceg profile image
Ben Ceglowski

This is broken by @expo/webpack-config 0.12.20. And not just fast refresh: no refreshes happen at all.

The issue was opaque, but after enough digging I found pinning that dependency to @0.12.17 restored fast refresh functionality.

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benceg profile image
Ben Ceglowski

Followup: I no longer experience this problem with @expo/webpack-config 0.12.25.

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deebov profile image
Dilshod Turobov

it doesn't seem to work for me

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deebov profile image
Dilshod Turobov

ah nevermind. it worked after upgrading Expo

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ajinkyax profile image
Ajinkya Borade

I was an expo fan, untill I started using Flutter :)

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yoyooo profile image
yoyooo

EXPO is my favorite

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kakavip profile image
Phạm Quý Hải

Current not working. please update