- For some reason, the typescript compiler chokes on platform-specific files (e.g. `foo.native.ts`) but only when compiling for Web thus far. Therefore we always have one version of the file which doesn't use a platform specifier, and that should bee the Web version. ([More info](https://stackoverflow.com/questions/44001050/platform-specific-import-component-in-react-native-with-typescript).)
The `metro.config.js` file rewrites a couple of imports. This is partly to work around missing features in Metro, and partly to patch the bundle. Affected imports include:
For native builds, we must provide a polyfill of `webcrypto`. We use a custom native module AppSecureRandom (based on [react-native-securerandom](https://github.com/robhogan/react-native-securerandom)) for the CRNG and [msrcrypto](https://github.com/kevlened/msrCrypto) for the cryptography.
The auth flow is based on a browser app which is specified by the `REACT_APP_AUTH_LOBBY` env var. The app redirects to that location with the UCAN request, and then waits for a redirect back. In the native platforms with proper support, it will do this using an in-app browser. In native without in-app browser, or in the Web platform, it will handle this with redirects. The ucan is extracted from the hash fragment of the "return url" which is provided either by the in-app browser in response or detected during initial setup in the case of redirects.
