Expo Mega Demo

Experimenting with new awesome React Native + Expo features.

Work in progress. More info soon.

A preview video (click the image):

Core features:

⚠️ Caution! Many features used in this demo are in early, experimental stage and they're not ready for production. Use on your own risk.

• Uses Expo custom managed workflow. Prebuilds on Expo SDK 43 pre-alpha template.
• All native changes (even these unusual) and patches are covered with config plugins and yarn postinstall script.
• Uses Expo Dev Client, react-navigation, ui-kitten
• Bluetooth communication using react-native-ble-plx with config plugin
• Color picker using Expo GL, made from this tutorial from William Candillon, but rewritten to Reanimated v2
• Music Picker is an expo-module written using Swift "Sweet" API. More info soon.
• JSI real-time Audio streaming, taken from this PR, thank you Marc!
• Player controls stolen from NCL (internal Expo rn-tester equivalent).
• FFT is calculated in the JS thread. The spectrum bin heights are written to SharedValues and animated with Reanimated 2.

  There is plan to use react-native-multithreading and calculate it in a separate thread. But even without that, the JS keeps around 57-59 fps.

• Hardware: Arduino Uno and the HM-10 BLE 4.0 module. Read more in the Hardware README.

How to run

First time:

1. Make sure you have Expo and all the stuff installed and configured (including Xcode)
2. yarn install
3. yarn prebuild
4. Copy AppDelegate.m from patches dir to ios/expomegademo directory - see below why.
5. yarn run:ios

Just to start the bundler (without rebuilding client): run yarn start.

Known issues

Most of them are caused by using very early SDK 43 stuff, which is not yet published, and other published packages are not yet compatible.

• expo-dev-client config plugin is not yet working with SDK 43 alpha.
  • It hangs the CLI for Android at the dangerousMod -> Main Activity so the -p ios must be added to the prebuild command.
  • It messes up the AppDelegate.m. Workign version can be found in ./patches/AppDelegate.m - need to be copied manually.
• Frequency bin labels are wrong 🤷 . Eventually I needed to display them in log scale and I am too lazy to think about how to recalculate everything properly.
• Modifying the sound.onAudioSampleReceived callback and the Reanimated 2 stuff requires at least picking the song again to reload properly, sometimes whole app restart is needed.
• Does not work on emulator.
• Not yet works for Android
  • No JSI-related expo-av changes applied.
  • The MusicPicker module isn't implemented yet for that platform (there's a copy-pasted expo-haptics code ¯_(ツ)_/¯)

Applied patches

See the postinstall.js script and the plugins section of app.json to see how the patches are applied

• patch-package for expo-gl and related libraries - needed, because of migration from @unimodules/core to expo-modules-core
• new expo-modules-autolinking requires modules to be specified in package.json dependencies. I don't want to copy my custom native modules to node_modules they are deleted after being copied there by yarn.
• by default, expo modules are built with xcframework if available, but that does not work for patched expo-gl, so its xcframework is deleted force build from source.
• expo-gl installs wrong expo-modules-core dependency in its own node_modules - it is deleted, the global node_modules one is correct.
• expo-cli built-in plugins sets the Push Notifications capability even when expo-notifications are not installed and I see no way to disable it. Another plugin was written to delete that entitlement.
• iOS requires another Info.plist value about Media Library usage permission - a config plugin takes care of that
• The custom_native_modules directory needs to be added to autolinking paths in Podfile. A config plugin takes care of that.
• The AppDelegate.m is being broken by expo-dev-client config plugin, wrote another config plugin to copy the patched file - it does not work, still need to copy it manually.