Expo Adapter

Installation

npm install @hot-updater/expo --save-dev

Configuration

interface ExpoAdapterConfig {
  outDir?: string;      // Output directory (default: "dist")
  sourcemap?: boolean;  // Generate sourcemaps (default: false)
  resetCache?: boolean; // Reset Metro cache before bundling (default: true)
}

Usage

import { expo } from '@hot-updater/expo'; 
import { defineConfig } from 'hot-updater';

export default defineConfig({
  build: expo({ 
    sourcemap: false
  }), 
  // ... other config
});

Expo configuration

The @hot-updater/expo package also provides the Expo config plugin. Add it to your app.json file:

{
  "expo": {
    "plugins": [
      [ 
        "@hot-updater/expo", 
        { 
          "channel": "production"
        } 
      ] 
    ]
  }
}

The app config plugin accepts these options:

For signed updates, add publicKeyPath: "./keys/public-key.pem" to this app plugin's options. It requires an RSA SPKI PEM public key of at least 2048 bits. Prebuild reads only this public file, embeds it in both native apps, and includes it in their fingerprints. It does not need the private key or KMS credentials. Configure the signer separately in hot-updater.config.ts.

See Expo and EAS signing setup for exporting the public file and releasing the matching native app.

Run prebuild to apply the changes:

npx expo prebuild

Expo DOM Components (use dom)

Expo DOM components need Expo SDK 55 or later and the Babel plugin below. The rest of the Expo adapter also works on earlier SDKs.

A DOM component loads its web bundle from the files built into the app. Once Hot Updater installs an update, the Babel plugin points each DOM component at the update's copy through overrideUri, a prop Expo supports from SDK 55 (expo/expo#40397). Without an installed update, the component keeps its built-in files. The components need no code changes.

Babel plugin

Create babel.config.js if your project does not have one:

npx expo customize babel.config.js

Then add the plugin:

module.exports = function (api) {
  api.cache(true);

  return {
    presets: ['babel-preset-expo'],
    plugins: [
      '@hot-updater/expo/babel-plugin', 
    ],
  };
};

Key features

• Uses Expo's expo export:embed command
• Auto-detects Hermes from app.json configuration
• Supports both managed and bare Expo workflows
• Compatible with Expo prebuild for native builds
• Automatically configures bundler based on Expo settings