Bitcoin Dev Kit — React Native

React Native language bindings for the Bitcoin Development Kit.

The code in this repository is mostly comprised of:

• Build tools and workflows
• CI workflows
• Tests
• Docs

The core Rust code that is exposed to the React Native language bindings actually resides in the bdk-ffi repository. This repo pulls it in as a submodule.

Notes for developers

See the docs at https://jhugman.github.io/uniffi-bindgen-react-native/guides/rn/getting-started.html for more advanced information on how to build this library.

To build the library and start testing locally, you must have:

• The Rust toolchain installed on your machine
• Set the default Rust toolchain to 1.90.0 (currently Rust stable)
• The just cli tool
• Initiated the submodule (just submodule-init)
• Installed your Rust compilation targets

Building the library and running the example wallet

The example/ directory contains a full-featured example wallet app that uses workspaces for development.

# Clone the repo and install prerequisites
git clone git@github.com:bitcoindevkit/bdk-react-native.git
cargo install cargo-ndk
yarn install

# Install compilation targets, for example:
rustup target add aarch64-linux-android aarch64-apple-ios aarch64-apple-ios-sim

# Build the library
just rename-library
just build-android

# Start an Android emulator and run the example app
yarn example start    # In terminal 1
yarn example android  # In terminal 2

Running the IntegrationTestingApp

The IntegrationTestingApp/ directory contains a standalone test app that uses the library as a tarball dependency (similar to how end-users would consume it). This app is not part of the workspace and is completely decoupled from the library development.

# First, build and package the library
just build-android
npm pack  # Creates bdk-rn-0.1.0.tgz

# Install dependencies in the IntegrationTestingApp
cd IntegrationTestingApp
npm install

# Run the app
npm run android  # or npm run ios

# See tests results in the emulator or capture the logs from your shell
adb logcat -s ReactNativeJS | tee tests.log

Workflow for testing library changes

When you make changes to the bdk-rn library and want to test them in the IntegrationTestingApp:

# Make local changes to the Rust code in bdk-ffi/bdk-ffi/src/

# Recompile the libary
just build-android

# Build the tarball
npm pack  # Creates updated bdk-rn-0.1.0.tgz

# Reinstall in IntegrationTestingApp
cd IntegrationTestingApp
npm install ../bdk-rn-0.1.0.tgz

Notes

1. The cargo-ndk library removed the --no-strip argument and this is creating a build error when using the latest release of uniffi-bindgen-react-native (0.29.3-1). We are currently building using a commit on their main branch which contains the patch. See the package.json file.
2. For some reason the example app doesn't work on my Pixel 8 API 35 emulator, but does work on the Pixel 5 API 31 and the Pixel 9 API 36. If you get a red banner at the top of the app when launching saying Unable to load script... and asking you to start Metro, try the example in a different emulator!