Embed Bare in a React Native app

Install the kitCopy Anchor Link

Install react-native-bare-kit, and bare-stow to link Bare Kit into the app. bare-stow wraps the worklet entry in code that imports bare-stow-runtime, so install that too:

npm i react-native-bare-kit b4a bare-stow-runtime
npm i -D bare-stow

From 0.17.0, react-native-bare-kit doesn't include Bare Kit itself, so the app links it in the next steps. For Expo, use the config plugin of expo-bare-kit 0.3.0 or later, which links Bare Kit and the workers you list in its workers option. The worklet code below is identical. Upgrading an app from 0.16 or earlier? See Migrate to Bare Kit 3.

Write the Bare coreCopy Anchor Link

The worklet entry script runs on its own thread. It reaches the host through Bare.IPC, a duplex stream. Here it echoes back whatever it receives:

// app.js—runs inside the worklet
const IPC = Bare.IPC

IPC.on('data', (data) => {
  const message = data.toString()
  IPC.write(Buffer.from(`echo: ${message}`))
})

This is ordinary Bare code: it can require any bare-* module and open a Hyperswarm or Corestore just as it would on the desktop.

Link Bare Kit into the appCopy Anchor Link

Pass the worklet's entry point to bare-stow link. It writes a Swift package and a Gradle module that bring in Bare Kit, through bare-kit-swift and bare-kit-kotlin, along with any native addons and assets that the core loads:

npx bare-stow link --target bare-kit --language swift --out ios/BareKitResources app.js
npx bare-stow link --target bare-kit --language kotlin --language-option package=com.example.addons --out android/bare-kit-resources app.js

Add the Swift package to the app target in Xcode, together with its bare-stow folder if the core references assets. Include the Gradle module in the Android app. bare-kit-kotlin is published on JitPack and needs Kotlin 2.4 or later and Android 10 (API level 29) or later, so add maven { url "https://jitpack.io" } to the app's repositories and raise kotlinVersion and minSdkVersion if they're lower. Run the commands again whenever the core's dependencies change. Without Bare Kit in the app, new Worklet() throws. See Linking addons and assets.

On iOS, also sign the app with the com.apple.developer.kernel.extended-virtual-addressing entitlement, which Bare Kit 3.1.0 and later need on a device. See iOS entitlement.

Start the worklet from React NativeCopy Anchor Link

In your React Native component—for example App.tsx, not the worklet's /app.js—create a Worklet, start it with the core's source, and read and write the IPC object it exposes:

import { Worklet } from 'react-native-bare-kit'
import b4a from 'b4a'

const source = `
const IPC = Bare.IPC
IPC.on('data', (data) => IPC.write(Buffer.from('echo: ' + data.toString())))
`

const worklet = new Worklet()
worklet.start('/app.js', source)

const { IPC } = worklet
IPC.on('data', (data) => console.log(b4a.toString(data)))
IPC.write(b4a.from('Hello from React Native!'))

The worklet honours the Bare lifecycle, so call worklet.suspend() and worklet.resume() from your app's background/foreground handlers to keep the core in step with the OS.

Run itCopy Anchor Link

Build and run on a simulator or device with your usual React Native toolchain. Worklet console.* output is written to the system log under the bare identifier—view it with the platform's native logging tools (Console.app on iOS, logcat on Android).

echo: Hello from React Native!