@ethicdevs/metro-webpack-react-native-web-babel-preset

A babel preset that configures itself for both metro with react-native and webpack with react-native-web. Use this instead of module:metro-react-native-babel-preset in your Babel config file.

Usage

Install with either npm or yarn (as you prefer). core-js@3 is a peer dependency and you might need to install it seperately.

yarn add -D core-js@3 @ethicdevs/metro-webpack-react-native-web-babel-preset

Add this to your Babel config file (babel.config.js):

module.exports = {
  presets: ["@ethicdevs/metro-webpack-react-native-web-babel-preset"],
};

With noPresetEnv option

If you want to provide your own preset-env config (in babel.config.js or babel-loader config, etc), you can exclude @babel/preset-env with the option noPresetEnv.

module.exports = {
  presets: [
    ["@ethicdevs/metro-webpack-react-native-web-babel-preset", { noPresetEnv: true }],
  ],
};

Behaviour

When bundling with metro, it simply includes module:metro-react-native-babel-preset so it shouldn't mess with your normal react native build.

When bundling with webpack/babel-loader, it includes the presets for typescript and flow, the react-native-web plugin, and the plugins from module:metro-react-native-babel-preset that aren't better handled by @babel/preset-env: react/jsx specific stuff and proposal features. It also includes @babel/preset-env set up to automatically pick up .browserslistrc or browserlist key in package.json and include appropriate polyfills.

When running in any other environment, it falls back to the same config as for webpack.

Using with webpack

With this preset, you can bundle a basic react native app for the web with very little or technically no webpack config.

You need to install at least webpack, babel-loader and probably babel-cli.

A minimal webpack.config.js would be:

const path = require("path");

module.exports = {
  module: {
    rules: [
      {
        test: /\.(js|jsx|tsx|ts|mjs)$/,
        include: [path.resolve(__dirname, "src")],
        use: {
          loader: "babel-loader",
        },
      },
    ],
  },
  resolve: {
    extensions: [
      ".web.js",
      ".js",
      ".web.ts",
      ".ts",
      ".web.tsx",
      ".tsx",
      ".web.mjs",
      ".mjs",
    ],
  },
};

And technically no config file with this command (doesn't work great though)

npx webpack --module-bind js=babel-loader

Don't forget to add a .browserslistrc to your root directory or your bundle will be huge. For example:

>0.5%
not ie 11
not samsung < 8

Magic bit

module.exports = ({ caller }) => {
  // is either "metro" or "babel-loader"
  const runningIn = caller(({ name }) => name);
  return {
    /* your config here */
  };
};

Changelog

• 1.4.1 add note to readme
• 1.4.0 require() all babel presets and plugins so they can be resolved even if they are installed in nested node_modules. Is this what you're supposed to do? Well it works...
• 1.3.1 actually add it as a dependency, should have started on 0.x
• 1.3.0 make core-js a peer dependecy
• 1.2.0 add babel-plugin-react-native-web as dependency, oops
• 1.1.0 add babel-plugin-module-resolver as dependency
• 1.0.0 Initial Release